cbse paper solutions 2012

8/11/2019 CBSE Paper Solutions 2012

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Important Instructions:

1. The Answer Sheet is inside this Test Booklet. When you are directed to open the Test Booklet, take outthe Answer Sheet and fill in the particulars onside-1andside-2carefully withblue/blackball point penonly.

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CBSE Prelim. 2012(Hints & Solutions) - Code C Narayana IIT/PMT Academy

NARAYANA INSTITUTE :A-1/171 A, Janakpuri, N.D.58; 196/197/D-12, Sec.-8, Rohini, N.D.-85,; E-14, South Extn.-II, N.D-49; H.O.:Vittalwadi, Narayanaguda, Hyderabad-29

[2 ]

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HINTS & SOLUTIONS

for

CBSE Preliminary 2012by Narayana IIT/PMT ACADEMY

1. Even in absence of pollinating agents seed-setting is assured in

(1) Zostera (2) Salvia (3) Fig (4)CommellinaSol: It has cleistogamous flowers.2. If one strand of DNA has the nitrogenous base sequence as ATCTG, what would be the complementary RNA

strand sequence?(1) UAGAC (2) AACTG (3) ATCGU (4) TTAGU

3. PCR and Restriction Fragment Length Polymorphism are the methods for(1) Genetic transformation (2) DNA sequencing(3) Genetic Fingerprinting (4) Study of enzymes

4. Which one of the following is correctly matched?(1) Apoplast Plasmodesmata (2) Potassium Readily immobilisation(3) Bakane of rice seedlings F. Skoog (4) Passive transport of nutrients ATP

5. Given below is the representation of a certain event at a particular stage of a type of cell division. Which is thisstage?

(1) Prophase II during meiosis (2) Prophase of Mitosis(3) Both prophase and metaphase of mitosis (4) Prophase I during meiosis

Sol: This stage is Pachytene of prophase-I of meiosis, it represent crossing over.

6. The cyanobacteria are also referred to as(1) golden algae (2) slime moulds (3) blue green algae (4) protists7. Cycas andAdiantumresemble each other in having

(1) Motile Sperms (2) Cambium (3) Vessels (4) Seeds8. Which one of the following is the correct statement for respiration humans?

(1) Neural signals from pneumotoxic centre in pons region of brain can increase the duration of inspiration(2) Workers in grinding and stone-breaking industries may suffer, from lung fibrosis(3) About 90% of carbon dioxide (CO

2) is carried by haemoglobin as carbamino-haemoglobin

(4) Cigarette smoking may lead to inflammation of bronchi

Sol: It is occupational lung disease.


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9. The common bottle cork is a product of

(1) Phellogen (2) Xylem (3) Vascular Cambium (4)Dermatogen

10. Select the correct statement from the ones given below with respect toPeriplaneta americana

(1) Males bear a pair of short thread like anal styles

(2) There are 16 very long Malpighian tubules present at the junction of midgut and hindgut

(3) Grinding of food is carried out only by the mouth parts(4) Nervous system located dorsally, consists of segmentally arranged ganglia joined by a pair of longitudinal

connectives

11. Which one of the following is not a property of cancerous cells whereas the remaining three are?

(1) They do not remain confined in the area of formation

(2) They divide in an uncontrolled manner

(3) They show contact inhibition

(4) They compete with normal cells for vital nutrients

12. Closed vascular bundles lack

(1) Conjunctive tissue (2) Cambium (3) Pith (4) Ground tissue

13. Common cold differs from pneumonia in, that(1) Pneumonia can be prevented by a live attenuated bacterial vaccine whereas the common cold has no

effective vaccine

(2) Pneumonia is caused by a virus while the common cold is caused by the bacteriumHaemophilusinfluenzae

(3) Pneumonia pathogen infects alveoli whereas the common cold affects nose and respiratory passage butnot the lungs

(4) Pneumonia is a communicable disease whereas the common cold is a nutritional deficiency disease

14. Which one of the following is wrong statement?

(1) Root nodule forming nitrogen fixers live as aerobes under free-living conditions

(2) Phosphorus is a constituent of cell membranes, certain nucleic acids and all proteins(3) Nitrosomonas andNitrobacterare chemoautotrophs

(4) Anabaena andNostoc are capable of fixing nitrogen in free-living state also

15. A normal-visioned man whose father was colour-blind, marries a woman whose father was also colour-blind.They have their first child as a daughter. What are the chances that this child would be colour-blind?

(1) zero percent (2) 25% (3) 50% (4) 100%

16. Placentation of tomato and lemon is

(1) Free central (2) Marginal (3) Axile (4) Parietal

17. Consumption of which one of the following foods can prevent the kind of blindness associated with vitaminA deficiency?

(1) Canolla (2) Golden rice (3) Bt-Brinjal (4) Flaver Savr tomato18. What is correct to say bout the hormone action in humans?

(1) Secretion of thymosins is stimulated with aging

(2) In females, FSH first binds with specific receptors on ovarian cell membrane

(3) FSH stimulates the secretion of estrogen and progesterone

(4) Glucagon is secreted by -cells of Islets of Langerhans and stimulates glycogenolysis

19. Which one is themostabundant protein in the animal world?

(1) Haemoglobin (2) Collagen (3) Insulin (4) Trypsin


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20. In which one of the following options the two examples are correctly matched with their particular type ofimmunity?

Examples Type of immunity

(1)Anti-tetanus and anti-snake bite injections,

Active immunity

(2) Saliva in mouth andTears in eyes Physical barriers

(3)

Mucus coating ofepithelium l ining theurinogenital tact and theHCl in stomach

Physiologicalbarriers

(4)Polymorpho-nuclearleukocytes andmonocytes

Cellular barriers

21. Cirrhosis of liver is caused by he chronic intake of

(1) Alcohol (2) Tobacco (Chewing) (3) Cocaine (4) Opium

22. F2generation ion a Mendelian cross showed that both genotypic and phenotypic ratios are same as 1 : 2 : 1.

It represents a case of

(1) Dihybrid cross (2) Monohybrid cross with complete dominance

(3) Monohybrid cross with incomplete (4) Co-dominance

23. In which one of the following, the genus name, its two characters and its phylum are not correctly matched,whereas the remaining three are correct?

Sol: Pila, is the member of phylumMolluscais unsegmented.

24. Motile zygote ofPlasmodium occurs in

(1) Salivary glands ofAnopheles (2) Human RBCs

(3) Human liver (4) Gut of femaleAnopheles

Sol: Motile zygote of plasmodium is ookinete and is occur in gut of Anopheles.

25. What was the most significant trend in the evolution of modern man (Homo sapiens) from his ancestors?

(1) Binocular vision (2) Increasing cranial capacity

(3) Upright posture (4) Shortening of jaws


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26. Given below is the diagrammatic representation of one of the categories of small molecular weight organiccompounds in the living tissues. Identify thecategoryshown and the one blankcomponent X in it.

Category Component

(1) Amino acid NH2

(2) Nucleotide Adenine

(3) Nucleoside Uracil

(4) Cholesterol Guanin

27. Widal Test is carried out to test

(1) Diabetes mellitus (2) HIV/AIDS (3) Typhoid fever (4) Malaria

28. Identify the possible link A in the following food chain

Plantinsectfrog A Eagle

(1) Wolf (2) Cobra (3) Parrot (4) Rabbit29. In a normal pregnant woman, the amount of total gonadotropin activity was assessd. The result expected

was

(1) High level of circulating HCG to stimulate endometrial thickening

(2) High levels of FSH and LH in uterus to stimulate endometrial thickening

(3) High level of circulating HCG to stimulate estrogen and progesterone synthesis

(4) High level of circulating FSH and LH in the uterus to stimulate implantation of the embryo

30. A nitrogen-fixing microbe associated withAzollain rice fields is

(1) Anabaena (2) Frankia (3)Tolypothrix (4)Spirulina

31. Compared to those of humans, the erythrocytes in frog are

(1) nucleated and with haemoglobin (2) very much smaller and fewer(3) nucleated and without haemoglobin (4) without nucleus but with haemoglobin

32. Select thecorrectstatement regarding the specific disorder of muscular or skeletal system

(1) Osteoporosis decrease in bone mass and higher chance of fractures with advancing age

(2) Myasthenia gravis Auto immune disorder which inhibits sliding of myosin filaments

(3) Gout inflammation of joints due to extra deposition of calcium

(4) Muscular dystrophy age related shortening of muscles

33. How many plants in the list given below have composite fruits that develop from an inflorescence?

Walnut, poppy, radish, fig, pineapple, apple, tomato, mulberry

Sol: Fig Syconus, Pineaple and Mulberry Sorosis.

(1) Five (2) Two (3) Three (4) Four34. Water containing cavities in vascular bundles are found in

(1) Maize (2) Cycas (3)Pinus (4) Sunflower

35. Which one of the following doesnotdiffer inE.coliandChlamydomonas?

(1) Chromosomal Organization (2) Cell wall

(3) Cell membrane (4) Ribosomes

Ans. (3)

Sol:E.colibacteria having different chromosomal Organization, Cell wall and Ribosome but does not differ inCell membrane fromChlamydomonas?


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36. The maximum amount of electrolytes and water (70 80 percent) from the glomerular filtrate is reabsorbedin which part of the nephron?

(1) Distal convoluted tubule (2) Proximal convoluted tubule

(3) Descending limb of loop of Henle (4) Ascending limb of loop of Henle

37. Which one is atruestatement regarding DNA polymerase used in PCR?

(1) It serves as a selectable marker (2) It is isolated from a virus

(3) It remains active at high temperature

(4) It is used to ligate introduced DNA in recipient cells

Sol: Enzyme taq polymerase is thermostable.

38. An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is

(1) Sporopollenin (2) Lignin (3) Cellulose (4) Cuticle

39. Yeast is used in the production of

(1) Lipase and pectinase (2) Bread and beer

(3) Cheese and butter (4) Citric acid and lactic acid

40. Phyllode is present in

(1) Euphorbia (2) Australian Acacia (3)Opuntia (4)Asparagus

41. Which one of the following is an example of carrying out biological control of pests/diseases using microbes?

(1) Nucleopolyhedrovirus against white rust inBrassica

(2) Bt-cotton to increase cotton yield

(3) Lady bird beetle against aphids in mustard

(4) Trichodermasp. against certain plant pathogens

42. In an area where DDT had been used extensively the population of birds declined significantly because

(1) earthworms in the area got eradicated (2) cobras were feeding exclusively on birds

(3) many of the birds eggs laid, did not hatch (4) birds stopped laying eggs

43. Pheretimaand its close relatives derive nourishment from

(1) decaying fallen leaves and soil organic matter (2) soil insects

(3) small pieces of fresh fallen leaves of maize, etc (4) sugarcane roots

44. Signals for parturition originate from

(1) Oxytocin released from maternal pituitary (2) Placenta only

(3) Fully developed foetus only (4) Both placenta as well as fully developed foetus

45. Gymnosperms are also called soft wood spermatophytes because they lack

(1) Phloem fibres (2) Thick-walled tracheids (3) Xylem fibres (4)Cambium

46. The Leydig cells as found in the human body are the secretory source of

(1) intestinal mucus (2) glucagon (3) androgens (4) progesterone

47. For transformation, micro-particles coated with DNA to be bombarded with gene gun are made up of

(1) Platinum or Zinc (2) Silicon or Platinum (3) Gold or Tungsten (4) Silver or Platinum

48. Removal of RNA polymerase III from nucleoplasm will affect the synthesis of

(1) hn RNA (2) m RNA (3) r RNA (4) t RNA

49. A person entering an empty room suddenly finds a snake right in front on opening the door. Which one of thefollowing is likely to happen in his neuro-hormonal control system?

(1) Neurotransmitters diffuse rapidly across the cleft and transmit a nerve impulse

(2) Hypothalamus activates the parasympathetic division of brain

(3) Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal cortex

(4) Sympathetic nervous system is activated releasing epinephrin and norepinephrin from adrenal medulla


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50. The test-tube Baby Programme employs which one of the following techniques?

(1) Intra uterine insemination (IUI) (2) Gamete intra fallopian transfer (GIFT)

(3) Zygote intra fallopian transfer (ZIFT) (4) Intra cytoplasmic sperm injection(ICSI)

51. People who have migrated from the planes to an area adjoining Rohtang Pass about six months back

(1) are not physically fit to play games like football

(2) suffer from altitude sickness with symptoms like nausea, fatigue, etc.

(3) have the usual RBC count but their haemoglobin has very high binding affinuty to O2

(4) have more RBCs and their haemoglobin has a lower binding affinity to O2

52. During gamete formation, the enzyme recombinase participates during

(1) Anaphase II (2) Prophase I (3) Prophase II (4) Metaphase I

Sol: Recombinase help in recombination (crossing over) occur during prophase-I

53. Which part of the human ear plays no role in hearing as such but is otherwise very much required?

(1) Organ of Corti (2) Vestibular apparatus (3) Ear ossicles (4) Eustachian tube

54. What is the figure given below showing in particular?

(1) Uterine cancer (2) Tubectomy (3) Vasectomy (4) Ovarian cancer

55. Which one of the following options gives one correct example each of convergent evolution and divergentevolution?

56. Companion cells are closely associated with

(1) Vessel elements (2) Trichomes (3) Guard cells (4) Sieve elements

57. The human hind brain comprises three parts, one of which is

(1) Corpus callosum (2) Cerebellum (3) Hypothalamus (4) Spinal cord

58. The upright pyramid of number is absent in(1) Forest (2) Lake (3) Grassland (4) Pond

59. Anxiety and eating spicy food together in an otherwise normal human, may lead to

(1) Jaundice (2) Diarrhoea (3) Vomiting 4) Indigestion

60. The coconut water and th eedible part of coconut are equivalent to

(1) Endocarp (2) Mesocarp (3) Embryo (4) Endosperm

61. Cymose inflorescence is present in

(1) Sesbania (2) Trifolium (3)Brassica (4)Solanum


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62. A process that makes important difference between C3and C

4plants is

(1) Glycolysis (2) Photosynthesis (3) Photorespiration (4) Transpiration

63. The extinct human who lived 1,00,000 to 40,00 years ago, in Europe, Asia and parts of Africa with shortstature, heavy eye brows, retreating fore heads, large jaws with heavy teeth, stocky bodies, a lumbering gaitand stooped posture was

(1) Neanderthal human (2) Cro-magnan humans (3)Ramapithecus (4)Homo habilis

64. A single strand of nucleic acid tagged with a radioactive molecule is called(1) Selectable marker (2) Plasmid (3) Probe (4) Vector

Sol: Probe is a short strand of RNA or DNA with radioactive nucleotides.

65. The highest number of species in the world is represented by

(1) Mosses (2) Algae (3) Lichens (4) Fungi

66. Which one out of A D given below correctly represents the structural formula of the basic amino acid?

(1) D (2) A (3) B (4) C

Sol: A basic amino acid contain more NH2group, as in option D two amino groups are present.]

67. Given below is an imaginary pyramid of numbers. What could be one of the possibilities about certainorganisms at some of the different levels?

(1) Level PP is phytoplanktons in sea and Whale on top level TC

(2) Level one PP is pipal trees and the level SC is sheep

(3) Level PC is rats and level SC is cats

(4) Level PC is insects and level SC is :small insectivorous birds

68. The figure below is the diagrammatic representation of theE.colivector pBR 322. Which one of the givenoptions correctly identifies its certain components (s)?

(1) rop-reduced osmotic pressure (2) Hind III, EcoRI-selectable markers

(3) ampR, tetR- antibiotic resistance genes (4) ori - original restriction enzyme


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69. Which one of the following is not a part of a transcription unit in DNA?

(1) A terminator (2) A promoter

(3) The structural gene (4) The inducer

70. A certain road accident patient with unknown blood group needs immediate blood transfusion. His one doctorfriend at once offers his blood. What was the blood group of the donor?

(1) Blood group AB (2) Blood group O (3) Blood group A (4) Blood group B

71. Vexillary aestivation si characteristic of the family

(1) Asteraceae (2) Solanaceae (3) Brassicaceae (4) Fabaceae

72. Measuring Biochemical Oxygen Demand (BOD) is a method used for

(1) working out the efficiency of oil driven automobile engines

(2) measuring the activity ofSaccharomyces cerevisaein producing curd on a commercial scale

(3) working out the efficiency of R. B. Cs. about their capacity to carry oxygen

(4) estimating the amount of organic matter in sewage water

73. Which one of the following is a case ofwrongmatching?

(1) Vector DNA - Site for t-RNA synthesis

(2) Micropropagation - In vitro production of plants in large numbers

(3) Callus - Unorganised mass of cells produced in tissue culture

(4) Somatic hybridization - Fusion of two diverse cells

Sol: Vector DNA Transfer of foreign DNA to target cell.

74. Nuclear membrane is absent in

(1) Agaricus (2) Volvox (3)Nostoc (4)Penicillium

75. Which one of the following statements isfalsein respect of viability of mammalian sperm?

(1) Survival of sperm depends on the pH of the medium and is more active in alkaline medium

(2) Viability of sperm is determined by its motility

(3) Sperms must be concentrated in a thick suspension

(4) Sperm is viable for only up to 24 hours

76. Which one of the following isnot a functional unit of an ecosystem?

(1) Decomposition (2) Productivity (3) Stratification (4) Energy flow

77. Monascus purpureusis a yeast used commercially in the production of

(1) streptokinase for removing clots from the blood vessels

(2) citric acid

(3) blood cholesterol lowering statins

(4) ethanol

78. Which one of the following is awrongstatement?

(1) Ozone in upper part of atmosphere is harmful to animals

(2) Greenhouse effect is a natural phenomenon

(3) Eutrophication si a natural phenomenon in freshwater bodies

(4) Most of the forests have been lost in tropical areas

79. Which one single organism or the pair of organisms iscorrectlyassigned to its or their named taxonomicgroup?

(1) Lichen is a composite organism formed from the symbiotic association of an algae and a protozoan

(2) Yeast used in making bread and beer is a fungus

(3) NostocandAnabaena are examples of protista

(4) ParameciumandPlasmodiumbelongs to the same kingdom as that ofPenicillium


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80. Ribosomal RNA is actively synthesized in

(1) Nucleolus (2) Nucleoplasm (3) Ribosomes (4) Lysosomes

81. What is true about ribosomes?

(1) These are composed of ribonucleic acid and proteins

(2) These are found only in eukaryotic cells

(3) These are self - splicing introns of some RNA s

(4) The prokaryotic ribosomes are 70 S, where S stands for sedimentation coefficient.

82. Which one of the following pairs of hormones are the examples of those that can easily pass through the cellmembrane of the target cell and bind to a receptor inside it (mostly in the nucleus)

(1) Thyroxin, Insulin (2) Somatostatin, oxytocin

(3) Cortisol, testosterone (4) Insulin, glucagon

83. Which one of the following microbes forms symbiotic association with plants and helps them in their nutri-tion?(1) Aspergillus (2) Glomus (3)Trichoderma (4)Azotobacter

84. Which one of the following isnota gaseous biogeochemical cycle in ecosystem?

(1) Phosphorus cycle (2) Nitrogen cycle (3) Carbon cycle (4) Sulphur cycle

85. Select the correct statement from the following regarding cell membrane(1) Proteins make up 60 to 70% of the cell membrane

(2) Lipids are arranged in a bilayer with polar heads towards the inner part(3) Fluid mosaic model of cell membrane was proposed by Singer and Nicolson(4) Na+and K+ions move across cell membrane by passive transport

86. Evolution of different species in a given area starting from a point and spreading to other geographical areasis known as

(1) Natural selection (2) Migration

(3) Divergent evolution (4) Adaptive radiation

87. Which one of the fallowing areas in India, is a hotspot of biodiversity?

(1) Gangetic Plain (2) Sunderbans (3) Western Ghats (4) Eastern Ghats

88. A patient brought to a hospital with myocardial infarction is normally immediately given

(1) Streptokinase (2) Cyclosporin-A (3) Statins (4) Penicillin

89. Which part would be most suitable for raising virus-free plants for micropropagation?

(1) Vascular tissue (2) Meristem (3) Node (4) Bark90. Maximum nutritional diversity is found in the group

(1) Animalia (2) Monera (3) Plantae (4) Fungi

91. Removal of introns and joining of exons in a defined order during transcription is called(1) Inducing (2) Slicing (3) Splicing (4) Looping

92. Best defined function of Manganese in green plants is(1) Calvin cycle (2) Nitrogen fixation (3) Water absorption (4) Photolysis of water

93. The gynoecium consists of many free pistils in flowers of(1) Tomato (2) Papaver (3)Michelia (4)Aloe

94. Both, autogamy and geitonogamy are prevented in

(1) Cucumber (2) Castor (3) Maize (4) Papaya95. The correct sequence of cell organelles during photorespiration is

(1) Chloroplast, Rough Endoplasmic reticulum Dictyosomes

(2) Chloroplast, mitochondria, peroxisome

(3) Chloroplast, vacuole, peroxisome

(4) Chloroplast, Golgibodies, mitochondria


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Sol: But the correct sequence for photorespiration is chloroplast peroxisomes mitochondria.

96. Which one of the following is common to multicellular fungi, filamentous algae and protonema of mosses?

(1) Members of kingdom Plantae (2) Mode of Nutrition

(3) Multiplication by fragmentation (4) Diplontic life cycle

97. Which one of the following is a correct statement?

(1) In gymnosperms female gametophyte is free-living

(2) Antheridiophores and archegoniophores are present in pteridophytes

(3) Origin of seed habit can be traced in pteridophytes

(4) Pteridophyte gametophyte has a protonemal and leafy stage

98. The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibioticsare the ones categorized as

(1) Archaebacteria (2) Chemosynthetic autotrophs

(3) Heterotrophic bacteria (4) Cyanobacteria

99. Which statement iswrongfor viruses?

(1) All of them have helical symmetry

(2) They have ability to synthesize nucleic acids and proteins

(3) Antibiotics have no effect on them

(4) All are parasites

100. Which one of the following iscorrectlymatched?

(1) Ginger-Sucker (2)Chlamydomonas Conidia

(3) Yeast Zoospores (4) Onion Bulb

101. ABC is an equilateral triangle with O as its centre.1F

,

2F

and3F

represents three forces acting along the

sides AB, BC and AC respectively. If the total torque about O is zero then the magnitude of3F

is

(1) F1 F

2(2) 1 2

F F2

(3) 2(F1+F

2) (4) F

1+F

2

Ans.(4)

Sol.1 2 3net F F F

1 2 30 F r F r F r

F3= F

1+ F

2

102. If the nuclear radius of27Al is 3.6 Fermi, the approximate nuclear radius of64Cu in Fermi is

(1) 1.2 (2) 4.8 (3) 3.6 (4) 2.4

Ans.(2)

Sol. 1/ 31 / 3 27

0 0 0r r A For Al 3.6 fm r 27 3r

r0= 1.2 fm

1 / 364 1 / 3

0For Cu r r A 1.2fm 64 4.8fm


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103. The height at which the weight of a body becomes 1/16th, its weight on the surface of earth (radius R), is:

(1) 15 R (2) 3 R (3) 4 R (4) 5 R

Ans.(2)

Sol. 22

1 Gmm Gmm

16 R R h

R h4 h 3R

R

104. A mixture consists of two radioactive materials A1and A

2with half lives of 20s and 10s respectively. Initially

the mixture has 40 g of A1and 160 g of A

2. The amount of the two in the mixture will become equal after:

(1) 80 s (2) 20s (3) 40 s (4) 60 s

Ans.(3)

Sol. After 40 sec, 40 gm of A1will become 10 gm and 160 gm of A

2will also become 10 gm (both are equal).

105. A geostationary satellite is orbiting the earth at a height of 5R above that surface of the earth, R being theradius of the earth. The time period of another satellite in hours at a height of 2R from the surface of theearth is:

(1) 10 (2) 6 2 (3) 6 / 2 (4) 5

Ans.(2)

Sol. 2 31 1T r ;2 32 2T r

32 32 2

32 31 1

3RT rT r 6R

R

2R5R

22

221

T 1 24T 6 2 hr

T 8 2 2

106. An electric dipole of moment p is placed in an electric field of intensity E. The dipole acquires a positionsuch that the axis of the dipole makes an angle with the direction of the field. Assuming that the potential

energy of the dipole to be zero when o90 , the torque and the potential energy of the dipole will respec-tively be :

(1) pE sin , 2pE cos (2) p E sin , 2 pE c os

(3) pE cos , pE sin (4) pE sin , pE cos

Ans.(4)

Sol. PEsin

+q

q

E

/ 2

U d PE sin d PE cos 0 PE cos


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[13]

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107. If voltage across a bulb rated 220 Volt - 100 Watt drops by 2.5% of its rated value, the percentage of therated value by which the power would decrease is:

(1) 2.5% (2) 5% (3) 10% (4) 20%

Ans.(2)

Sol.2V

PR

dP 2dv2 2.5 5%

P V

108. The horizontal range and the maximum height of a projectile are equal. The angle of projection of theprojectile is:

(1) 1tan 4 (2) 1tan 2 (3) o45 (4)1 1tan

4

Ans.(1)

Sol. 2 2 2u 2 sin cos u sin

R H

g 2g

tan 4 so, 1tan 4

109. In the circuit shown the cells A and B have negligible resistances. For VA= 12V,

1R 500 and R 100 the galvanometer (G) shows no deflection. The value of V

Bis

(1) 2 V (2) 12V (3) 6 V (4) 4 VAns.(1)

Sol. Applying Kirchoffs for loop connecting cell VA, R

1and A

2

500I 100I 12

So,2

212 10I 2 106

Hence, 2BV 100 2 10 2V

110. A milli voltmeter of 25 milli volt range is to be converted into an ammeter of 25 ampere range. The value (inohm) of necessary shunt will be

(1) 0.01 (2) 1 (3) 0.05 (4) 0.001Ans.(4)

Sol. Resistance of voltmeter is very high w.r.t. shunt, hence almost all current will pass through shunt.

G

voltmeter

25 A S

25 A25 mV

25 S = 25 mV

S 0.001


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[14]

[14]

111. The figure shows a logic circuit with two inputs A and B and the output C. The voltage wave forms acrossA, B and C are given. The logic circuit gate is:

(1) NOR gate (2) AND gate (3) NAND gate (4) OR gate

Ans.(4)

Sol.

A B Y A B Y

0 0 0 0 0 0

1 0 1 0 1 1

1 1 1 1 0 1

0 1 1 1 1 1

Y = A+ B OR gate

112. An alternating electric field, of frequencyv, is applied across the dees (radius = R) of a cyclotron that isbeing used to accelerate proton (mass = m). The operating magnetic field (B) used in the cyclotron and thekinetic energy (K) of the proton beam, produced by it, are given by:

(1)2 22 mB and K m R

e

(2) 2 2 22 m

B and K 2m Re

(3)2 2mB and K m R

e

(4)2 2 2mB and K 2m R

e

Ans.(2)

Sol. proton will change its velocity oppositely in time equal to half time period of AC source.

R 2 R

v v v 2 RT / 2 T

m 2 Rmv 2 mR R B

eB eB e

22 2 21K mv m 2 R 2m R

2 2

113. The current (I) in the inductance is varying with time according to the plot shown in figure

Which one of the following is the correct variation of voltage with time in the coil?

(1) (2) (3) (4)

Ans.(3)

Sol.02I tdI dV L L constant

dt dt T

; For t = 0 to t = T/2

02I tdI dV L L constantdt dt T

; For t = T/2 to t = T


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[15]

[15]

114. The magnifying power of a telescope is 9. When it is adjusted for parallel rays the distance between theobjective and eyepiece is 20 cm. The focal length of lenses are :(1) 15 cm, 5 cm (2) 18 cm, 2 cm (3) 11 cm, 9 cm (4) 10 cm, 10 cm

Ans.(2)

Sol.0

0 ee

f9 & f f 20

f

sop f0= 18, fe= 2115. If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the

rate of energy production is Q?

(1) 1/ 22Q/ 4 R

(2)

1/ 424 R Q / (3) 1/ 42Q/ 4 R (4) 2Q/ 4 R

( stands for Stefans constant)

Ans.(3)

Sol. Rate of energy 2 4Q 4 R T 1/ 4

2

QT

4 R

116. Electron in hydrogen atom first jumps from third excited state to second excited state and then from second

excited to the first excited state. The ratio of the wavelength1 2: emitted in the two cases is:

(1) 27/20 (2) 27/5 (3) 20/7 (4) 7/5Ans.(3)

Sol. 2 21 1

hc 1 1 hc 713.6 13.6

4 3 144

2 22

hc 1 113.6

3 2

2 1

2

1

hc

20hc 7

117. A 200 W sodium street lamp emits yellow light of wavelength 0.6 m . Assuming it to be 25% efficient inconverting electrical energy to light, the number of photons of yellow light it emits per second is:

(1) 6 1018 (2) 62 1020 (3) 3 1019 (4) 1.5 1020

Ans.(4)

Sol.34 8

19

7

hc 6.625 10 3 10E 3.2 10 J

6 10

201

nE 200W n 1.52 104 118. Four point charges Q, q, 2q and 2Q are placed, one at each corner of the square. The relation between Q

and q for which the potential at the centre of the square is zero is:

(1)1

Qq

(2) Q = q (3)1

Qq

(4) Q = q

Ans.(4)

Sol. If potential at centre is zero.

Then Q q +2q +2Q = 0

So Q = q


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[16]

[16]

119. An -particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of 0.25 Wb/m2.The de Broglie wavelength associated with the particle will be:

(1) 0.1 (2) 10 (3) 0.01 (4) 1

Ans.(3)

Sol.

mv

R qB ,

h h

mv qBR 0.01

120. A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It :

(1) will stay in any position (2) will stay in north-south direction only

(3) will stay in east- west direction only (4) will become rigid showing no movement

Ans.(1)

Sol. When compass needle is taken to a geometric pole, if will become free and it will stay in any position.

121. A ring is made of a wire having a distance0R 12 . Find the points A and B, as shown in figure, at which

a current carrying conductor should be connected so that the resistance R of the sub circuit between these

points is equal to8

3

(1)1

2

13

l

l(2)

1

2

38

l

l(3)

1

2

12

l

l(4)

1

2

58

l

l

Ans.(3)

Sol. Resistance per unit length1 2

12

l l

1 2

3 1 18 R R

Put1

11 2

12R

l

l land

22

1 2

12R

l

l l

on solving this1

2

12

l

l

122. C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because:

(1) In case of C the conduction band is partly filled even at absolute zero temperature(2) the four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the

third

(3) The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit

(4) In case of C the valance band is not completely filled at absolute zero temperature

Ans.(2)

Sol. Loosely bounded valence ein Si as compared to C.


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[17]

[17]

123. Transfer characteristics [output voltage (V0) vs input voltage (V

i)] for a base biased transistor in CE

configuration is as shown in the figure. For using transistor as a switch, it is used:

(1) both in region (I) and (III) (2) in region II(3) in region I (4) in region III

Ans.(1)Sol. Transistor as a switch is used in saturated and cut off region.124. Two spheres A and B of masses m

1and m

2respectively collide. A is at rest initially and B is moving with

velocity v along x-axis. After collision B has a velocityv

2in a direction perpendicular to the original direction.

The mass A moves after collision in the direction.

(1) opposite to that of B (2)1 1tan

2

to x-axis

(3)1 1tan

2

to x axis (4) same as that of B

Ans.(2)

Sol.i 2 1

p m vi m 0

f 2 1 1

v p m j m v2

; (v1= final velocity of A)

i f 2 2 1 1

v p p m vi m j m v2

2 21

1 1

m m v v vi jm m 2

1tan

2

1 1tan2

to the x-axis

125. When a string is divided into three segments of lengthl1,l

2andl

3the fundamental frequencies of these three

segments arev1,v

2andv

3respectively. The original fundamental frequency (v) of the string is:

(1) v= v1+ v

2+ v

3(2)

1 2 3

1 1 1 1

(3)1 2 3

1 1 1 1

(4) 1 2 3

Ans.(2)

Sol. 1 1 1 122

l l ; 11 1

v v2

l

22 2 222

l l ; 2

2 2

v v2

l


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[18]

[18]

33 3 322

l l ; 3

3 3

v v

2

l

31 2

1 2 3

22 21 1 1v v v

ll l

1 2 32 2 2 1

v

l l l

126. Two similar coils of radius R are lying concentrically with their planes at right angles to each other. Thecurrents flowing in them are I and 2I, respectively. The resultant magnetic field induction at the centre willbe:

(1) 03 I2R

(2) 0

I

2R

(3) 0

I

R

(4) 0

5 I

2R

Ans.(4)

Sol. 2 2 2 20 01 2I I 5

B B B 1 22R 2R

127. When a mass is rotating in a plane about a fixed point, its angular momentum is directed along:

(1) the line making an angle of 45 to the plane of rotation(2) the radius

(3) the tangent to the orbit

(4) a line perpendicular to the plane of rotation

Ans.(4)

Sol. L m r v

128. The motion of a particle along a straight line is described by equation: x = 8 + 12t t3, where x is in metreand t in second. The retardation of the particle when its velocity becomes zero, is:

(1) zero (2) 6 ms2 (3) 12 ms2 (4) 24 ms2

Ans.(3)Sol. x = 8 +12t t3

2dxv 12 3t 0 t 2secdt

t 2sec

dva 6t a 6 2 12

dt

a = 12 m/s2 retardation = 12 m/s2

129. A spherical planet has a mass Mpand diameter D

p. A particle of mass m falling freely near the surface of

this planet will experience an acceleration due to gravity, equal to:

(1) GMpm/Dp2 (2) GMp/Dp

2 (3) 4GMpm/Dp2 (4) 4GMp/Dp

2

Ans.(4)

Sol.

p P2 2

pp

GM m 4GM mF F

DD

2

p

g 2

p

4GMFa

m D


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[19]

[19]

130. A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gasduring the cycle is:

(1) 4 PV (2)1

PV2

(3) PV (4) 2PV

Ans.(4)

Sol. For a cycle Q W Area of the PV diagram 2PV

131. Liquid oxygen at 50 K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant.Which one of the following graphs represents the variation of temperature with time?

(1) (2) (3) (4)

Ans.(4)Sol. State change takes place from liquid to gas132. The damping force on an oscillator is directly proportional to the velocity. The units of the constant of

proportionality are:(1) kgms2 (2) kgs1 (3) kgs (4) kgms1

Ans.(2)

Sol.dF v

dF kv

21d

1

F kgmsk unit of k kgs

v ms

133. A particle has initial velocity 2 i 3 j

and acceleration 0.3i 0.2 j

. The magnitude of velocity after 10seconds will be:

(1) 5 2 units (2) 5units (3) 9units (4) 9 2 units

Ans.(1)

Sol. x y u 2i 3j u 2;u 3

x y a 0.3i 0.2j a 0.3;a 0.2

v u at v 2 0.3 10 i 3 0.2 10 j

v 5i 5j v 5 2 unit

134. Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground

state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The thresholdfrequency of the material is:

(1) 51015Hz (2) 1.61015Hz (3) 2.51015Hz (4) 41015Hz

Ans.(2)

Sol. 10.2eV 3.57 eV

6.63eV hv= 6.63

1915

34

6.63 1.6 101.6 10 Hz

6.67 10


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[20]

[20]

135. A ray of light is incident at an angle of incident, i, on one face of a prism of angle A (assumed to be small) andemerges normally from the opposite face. If the refractive index of the prism is , the angle of incidence i,is nearly equal to:

(1)A

2

(2) A (3) A / 2 (4) A

Ans.(4)Sol.

1 2i i A

1 A i 0 A

i A

A

i

136. Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is:

(1) Zero (2) 0.25 A (3) 0.5 A (4) 0.75 A

Ans.(3)

Sol. D2is reverse biased; D

1is forward biased

10

i

5 V

5i 0.5A

10

137. In a CE transistor amplifier, the audio signal voltage across the collector resistance of2k is 2V. If the baseresistance is 1k and the current amplification of the transistor is 100, the input signal voltage is:

(1) 1.0 V (2) 1 mV (3) 10 mV (4) 0.1 V

Ans.(3)

Sol. Current amplification factor :3C

C 3

B

I 2VI 10 A

I 2 10

2B BB B3

B

V VI V 10

R 1 10

100

Now,3

B3

B

10 1100 V volt 10mV

V 10 100


21/32


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[22]

[22]

Ans.(4)

Sol.d

E |100t |dt

at t = 2sec

E = 200 volt

E 200 1

i A 0.5AR 400 2 143. A concave mirror of focal length f

1 is placed at a distance d from a convex lens of focal length f

2. A

beam of light coming from infinity and falling on this convex lens - concave mirror combination returns toinfinity. The distance d must be

(1) f1+ f

2(2) 2f

1+ f

2(3)2f

1+ f

2(4) f

1+ f

2

Ans.(2)

Sol.1 2d 2f f

f2 2f1

144. The electric field associated with an e.m. wave in vacuum is given by 8E i40cos kz 6 10 t

, where E,

z and t are in volt/m, meter and seconds respectively. The value of wave vector k is:

(1) 0.5 m1 (2) 6 m1 (3) 3 m1 (4) 2 m1

Ans.(4)

Sol. 8 86 10 2 6 10

86 102

886 10C 3 10

2

12k 2 k 2m

145. A car of mass 1000 kg negotiates a banked curve of radius 90 m on a fictionless road. If the banking angleis 45, the speed of car is:

(1) 30 ms1 (2) 5 ms1 (3) 10 ms1 (4) 20 ms1

Ans.(1)

Sol.

2 2o v v

tan45 Rg 90 10

So, V = 30 m/sec

146. When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet ofglass. This implies that the liquid must have refractive index.

(1) less than one (2) greater than that of glass

(3) less than that of glass (4) equal to that of glass

Ans.(4)

Sol. If biconvex lens behave like plane sheet, ray will pass undeviated through it only when medium has samerefractive index as that of biconvex lens.


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[23]

[23]

147. A solid cylinder of mass 3 kg is rolling on a horizontal surface with velocity 4 ms1. It collides with a horizontalspring of force constant 200 Nm1. The maximum compression produced in the sprig will be:

(1) 0.6 m (2) 0.7 m (3) 0.2 m (4) 0.5 m

Ans.(1)

Sol. Loss in K.E. = Gain in spring energy

2 2 21 1 1

I mv kx2 2 2 Put2

1I mr2

148. What is the flux through a cube of side a if a point charge of q is at one of its centre:

(1)0

q

8 (2) 0

q (3)

2

0

q6a

2 (4) 0

2q

Ans.(1)

Sol. Since if charge q is placed at the corner of a cube then charge enclosed = q/8

Therefore,enclosed

cube0 0

q q8

149. An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocitythat the atom acquired as a result of photon emission will be:

(1)25hR24m (2)

25m2 4 h R (3)

24m2 5 h R (4)

24hR25m

(m is the mass of the electron, R, Rydberg constant and h Plancks constant)

Ans.(4)

Sol. 5 1hc

E E

Rhc hcRhc

25

24 1R25

h h 24 Rhp v

m 25 m

150. Two sources of sound placed close to each other, are emitting progressively waves given by

1y 4 sin 600 t and 2y 5 sin 608 t . An observer located near these two sources of sound will hear:

(1) 8 beats per second with intensity ratio 25 : 16 between waxing and waning




Ans.(3)

Sol.

2 2

1 2max2 2

min 1 2

A A 5 4I 81I 1A A 5 4

1 12 600 so 300 Hz

2 22 608 so 304 H z

No. of beats per sec =v2v1= 4


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[24]

[24]

151. In which of the following compounds, nitrogen exhibits highest oxidation state?

(1) NH3

(2) N3H (3) NH

2OH (4) N

2H

4

Ans. (2)

Sol.3N H

Oxidation state of nitrogen is - 1/3

152. Identify the wrong statement in the following(1) Amongst isoelectronic species, greater the negative charge on the anion, larger is the ionic radius.

(2) Atomic radius of the elements increases as one moves down the first group of the periodic table

(3) Atomic radius of the elements decreases as one moves across from left to right in the 2nd period of theperiodic table

(4) Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius

Ans. (4)

Sol.Amongst isoelectronic species, smaller the positive charge on the cation, bigger is the ionic radius.

153. Which one of the following is an outer orbital complex and exhibits paramagnetic behaviour?

(1) [Zn(NH3)

6]2+ (2) [Cr(NH

3)

6]2+ (3) [Co(NH

3)

6]2+ (4) [Ni(NH

3)

6]2+

Ans. (3)Sol. 23 6[Ni(NH ) ]

2 0 8Ni 4s , 3d

154. Maximum number of electrons in a subshell withl= 3 and n = 4 is :

(1) 16 (2) 10 (3) 12 (4) 14

Ans. (4)

Sol.l = 3. n = 4

Sub Energy level if 4f

Maximum No. of electron in f subshell = (14)

155.CH3CHO and C6H5CH2CHO can be distinguished chemically by:(1) Iodoform test (2) Tollens reagent test (3) Fehling solution test (4) Bendedict test

Ans. (1)

Sol.CH3CHO gives iodoform test, C

6H

5CH

2CHO does not give iodoform test

156.The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice of 0C is:

(1) 21.04 cal/(mol K) (2) 5.260 cal/(mol K)

(3) 0.526 cal/(mol K) (4) 10.52 cal/(mol K)

Ans. (2)

Sol.Enthalpy of fusion of H2O

3fusH 1.435 10

s cal / moleT 273

1 15.26cal. mole K

157. Which one of the following is a mineral of iron?

(1) Cassiterite (2) Pyrolusite (3) Magnetite (4) Malachite

Ans. (3)

Sol.Magnetite


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[25]

[25]

158.The pair of species with the same bond order is:

(1) O2+, NO+ (2) NO, CO (3) N

2, O

2(4) 22O

, B2

Ans. (4)

Sol.Both have bond order 1

159.Which of the following acids does not exhibit optical isomerism?

(1) -amino acids (2) Lactic acid (3) Tartaric acid (4) Maleic acidAns. (4)

Sol.Maleic acid (chiral centre is absent)

HCCOOH

HCCOOH

160. In the following sequence of reactions 3 4H O LiAlHKCN3 etherCH Br A B C

, the end product (C) is:

(1) Methane (2) Acetaldehyde (3) Ethyl alcohol (4) Acetone

Ans. (3)

Sol. 3 4H O LiAlHKCN3 3 3 3 2etherCH Br CH CN CH COOH CH CH OH

161.In the following reaction :

H CCCH=CH3 2

CH3

CH3

2H O/ H

A + B

The major product is:

Ans. (4)

Sol. H CCCH=CH3 2

CH3

CH3

2H O/ H

H CCCHCH3 3

CH3

CH3

+ 1,2 methylshift H CCCHCH3 3

CH3

CH3

+

H CCCHCH3 3

CH3

CH3

OH


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[26]

[26]

162.Which nomenclature is not according to IUPAC system?

(1)

CH CH CHCH CHCH ,3 2 2 3

CH3

Br CH3

4Bromo, 2, 4dimethylhexane

(2)

CH CHCHCH CH ,3 2 3

CH 3

2Methyl3phenylpentane

(3)

CH CCH CH CH COOH,3 2 2 2

O5oxohexanoic acid

(4)1Bromoprop2ene

BrCH CH=CH ,2 2

Ans. (4)Sol.The correct IUPAC nomenclature is

3Bromoprop1ene

163. In a reaction, A B Product, rate is doubted when the concentration of B is doubled, and rate increasesby a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law of the reactincan be written as:(1) Rate = k [A]2[B]2 (2) Rate = k [A] [B] (3) Rate = k [A]2[B] (4) Rate = k [A] [B]2

Ans. (3)

Sol.A + B productWhen concentration of B is double rate is double so order with respect to B is 1When the concentration of A and B are double the rate becomes 8 times. It indicates the order with A is 2Rate = k [A]2[B]

164. Bond order of 1.5 is shown by

(1) 2O (2) 22O

(3) O2 (4) 2O

Ans. (1)

Sol.2 2 2 2 2 2 2 2 1

z x y x y1s , *1s , 2s , * 2s , 2p , 2p 2p , * 2p * 2p

10 7B.O. 1.5

2

165. Predict the products in the given reaction.

CHO

Cl50%KOH


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[27]

[27]

Ans. (2)

Sol.Cannizzaro reaction

166. The ease of adsorption of the hydrated alkali metal ions on an ion-exchange resins follows the order:

(1) Rb+< K+< Na+< Li+ (2) K+< Na+< Rb+< Li+

(3) Na+< Li+< K+< Rb+ (4) Li+< K+< Na+< Rb+

Ans. (4)

Sol.Li+< K+< Na+< Rb+

larger the hydrated ionic radii lesser the rate of adsorption

167.Which one of the following pairs is isostrucural (i.e. having the same shape and hybridization)?

(1) [NH3and 3NO

] (2) [NF3and BF

3]

(3) 4 4[BF and NH ] (4) [BCl

3and BrCl

3]

Ans. (3)

Sol.Both 4 4[BF and NH ] are SP3hybridized and have same structure

168.PAand PBare the vapour pressure of pure liquid components, A and B respectively of an ideal binary solution.If x

Arepresents the mole fraction of component A, the total pressure of the solution will be

(1) PA

+ xA

(PA P

B) (2) P

B+ x

A(P

B P

A)

(3) PB+ x

A(P

A P

B) (4) P

A+ x

A(P

B P

A)

Ans. (3)

Sol.s A A B BP X P X P

=A A A BX P (1 X ) P

A A B A BX P P X P

S B A A BP P X (P P )

169.Standard enthalpy of vapourisation vapH for water at 100C is 40.66 kJ mol1. The internal energy of

vaporisation of water at 100C (in kJ mol1) is:

(1) 43.76 (2) +43.76 (3) +40.66 (4) +37.56

(Assume water vapour to behave like an ideal gas).

Ans. (4)

Sol. gH E n RT

gE H n RT

1 8.314 37340.66

1000

= 37.56170.Which of the following statements is false?

(1) Nylon-66 is an example of elastomer

(2) The repeat unit in natural rubber is isoprene

(3) Both starch and cellulose are polymers of glucose

(4) Artificial silk is derived from cellulose

Ans. (1)

Sol.Nylon-66 is an example of fiber


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[28]

[28]

171. Which one of the following is not a condensation polymer?(1)Glyptal (2) Dacron (3) Neoprene (4) Melamine

Ans. (3)Sol.Neoprene is addition polymer172.The number of octahedral void(s) per atom present in a cubic close - packed structure is:

(1) 3 (2) 2 (3) 4 (4) 1

Ans. (4)Sol.in C.C.P the effective no. of atom per unit cell = 4

in C.C.P the effective no. of octahedral voide = 4In C.C.P. structure number of octahedral void per atom 4/4 = 1

173. Which of the statements is not trure?(1) Na

2Cr

2O

7is preferred over K

2Cr

2O

7in volumetric analysis

(2) K2Cr

2O

7solution in acidic medium is orange

(3) K2Cr

2O

7solution becomes yellow on increasing the pH beyond 7

(4) On passing H2S trhough acidified K

2Cr

2O

7solution, a milky colour is observed.

Ans. (1)Sol. Na

2Cr

2O

4is hygroscopic in nature so it can not be used in volumetric analysis

174. The protecting power of lyophilic colloidal sol is expressed in terms of:(1) Gold number (2) Critical miscelle concentration(3) Oxidation number (4) Coagulation value

Ans. (1)Sol.Gold number175. Among the following compounds the one that is most reactive towards electrophilic nitration is:

(1) Nitrobenzene (2) Toluene (3) Benzene (4) Benzoic AcidAns. (2)Sol. In toluene CH

3is activating group for electrophilic aromatic substitution

176. pH of a saturated solutin of Ba(OH)2is 12. The value of solubility product (K

sp) of Ba (OH)

2is:

(1) 5.0 107 (2) 4.0 106 (3) 5.0 106 (4) 3.3 107

Ans. (1)Sol. Ba(OH)

2 has pH = 12

210[OH]

2

3Ksp 4s6 71 10 5 10

2

177. A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter ofthe metal atom is:(1) 408 pm (2) 144 pm (3) 204 pm (4) 288 pm

Ans. (4)

Sol.a 2 408 2

2r2 2

288pm

178. The correct order of decreasing acid strength of trichloroacetic acid (A), trifluoracetic acid (B), acetic acid(C) and formic acid (D) is:(1) B > D > C > A (2) A > B > C > D(3) A > C > B > D (4) B > A > D > C

Ans. (4)

Sol.Stronger the I effect more acidic the carboxylic acid


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[29]

[29]

179. The correct set of four quantum numbers for the valences electron of rubidium atom (Z = 37) is:

(1) 6, 0, 0, + 1/2 (2) 5, 0, 0, + 1/2 (3) 5, 1, 0 + 1/2 (4) 5, 1, 1, + 1/2

Ans. (2)

Sol.Z = 37

1[kr]5s

180. Aluminium is extracted from alumina (Al2O

3) by electrolysis of a molten mixture of:

(1) Al2O3+ CaF2+ NaAlF4 (2) Al2O3+ Na3AlF6+ CaF2(3) Al

2O

3+ KF + Na

3AlF

6(4) Al

2O

3+ HF + NaAlF

4

Ans. (2)

Sol.Al2O

3+ Na

3AlF

6+ CaF

2

181.Equimolar solutions of the following substances were prepared separately. Which one of these will recordthe highest pH value?

(1) Al Cl3

(2) Li Cl (3) Be Cl2

(4) Ba Cl2

Ans. (4)

Sol.Ba Cl2 (Solution is basic)182.When Cl

2gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine

changes from:

(1) Zero to 1 and zero to + 5(2) Zero to 1 and zero to + 3

(3) Zero to + 1 and zero to 3 (4) Zero to + 1 and zero to 5

Ans. (1)

Sol. 2 3 23Cl 6NaOH NaCl 5NaClO 3H O

183. Which one of the following statements is incorrect about enzyme catalysis?

(1) Enzyme action is specific

(2) Enzymes are denaturated by ultraviolet rays and at high temperature(3) Enzymes are least reactive at optimum temperature

(4) Enzymes are mostly proteinous in nature

Ans. (3)

Sol.Enzymes are most reactive at optimum temperature

184. Deficiency of vitamin B1causes the disease

(1) Beri-Beri (2) Cheilosis (3) Sterility (4) Convulsions

Ans. (1)

Sol.Beri-Beri

185. Which one of the following sets of monosaccharides forms sucrose?(1) D Glucopyranose and D fructofuranose

(2) D Glucopyranose and D fructofuranose

(3) D Glucopyranose and D fructopyranose

(4) D Galactopyranose and D Glucopyranose

Ans. (1)

Sol. D Glucopyranose and D fructofuranose


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[30]

[30]

186. Limiting molar conductivity of NH4OH

o

4i.e. m(NH OH )

is equal to:

(1)o o o

4m(NaOH ) m(NaCl) m(NH Cl)

(2)o o o

4 4 4m(N H OH ) m(N H Cl) m(NH Cl)

(3)o o o

4m(NH Cl) m(NaOH ) m(NaCl) (4)

o o o

4m(NH Cl) m(N aCl) m(N aOH ) Ans. (3)

Sol.o o o

4m(N H Cl) m(NaOH ) m(NaCl) (Kholraush law)

187. Which one of the following statements regarding photochemical smog is not correct?

(1) Photochemical smog is an oxidising agent in character

(2) Photochemical smog is formed through photochemical reaction involving solar energy

(3) Photochemical smog does not cause irritation in eyes and throat

(4) Carbon monoxide does not play any role in photochemical smog formation

Ans. (3)Sol.Photochemical smog cause irritation in eyes and throat

188. Buffer solutions have constant acidity and alkalinity because:

(1) acids and alkalies in these solutions are shielded from attack by other ions

(2) they have large excess of H+or OHions

(3) they have fixed value of pH

(4) these give unionised acid or base on reaction with added acid or alkali

Ans. (4)

Sol.these give unionised acid or base on reaction with added acid or alkali

189. Which one of the alkali metals, forms only, the normal oxide, M2O on heating in air?

(1) K (2) Li (3) Na (4) RbAns. (2)

Sol.Lithium form only monoxide when react with air

190. Which of the following species contains three bond pairs and one lone pair around the central atom?

(1) BF3

(2) 2NH (3) PCl

3(4) H

2O

Ans. (3)

Sol.PCl3(SP3hybridisation)

191. In a zero - order reaction for every 10 rise of temperature, the rate is doubled. If the temperature isincreased from 10C to 100C, the rate of the reaction will become:

(1) 512 times (2) 64 times (3) 128 times (4) 256 times

Ans. (1)Sol.New rate T/102192. A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element

undergoes maximum change in the oxidation number?

(1) H (2) Cl (3) C (4) S

Ans. (2)

Sol.Cl


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[31]

[31]

193.Acetone is treated with excess of ethanol in the presence of hydrochloric acid. The product obtained is:

Ans. (3)

Sol.Acetone with excess of ethanol gives acetal.

194.In Freundlich Adsorption isotherm, the value of 1/n is:

(1) between 2 and 4 in all cases (2) 1 in case of physical adsorption

(3) 1 in case of chemisorption (4) between 0 and 1 in all casesAns. (4)

Sol.between 0 and 1 in all cases

195. In which of the following reactions, standard reaction entropy change ( S ) is positive and standard Gibbss

energy change ( G ) decreases sharply with increasing temperature?

(1) 2 21

CO(g) O (g) CO (g)2

(2) 21

Mg O (g) MgO(s)2

(3) 2 21 1 1

C graphite O (g) CO (g)

2 2 2

(4) 21

C graphite O (g) CO(g)

2

Ans. (4)

Sol. 21

C graphite O (g) CO(g)2

(Ellingham diagram)

196. Sulphur trioxide canbe obtained by which of the following reaction:

(1) 2 4 3Fe (SO ) (2) 2 4S H SO

(3)2 4 5H S O PCl (4) 4CaSO C

Ans. (1)

Sol. 2 4 3 2 3 3Fe (SO ) Fe O 3SO 197. Which of the following statements is not valid for oxoacids of phosphorus?

(1) Hypophosphorous acid is a diprotic acid

(2) All oxoacids contain tetrahedral four coordinated phosphorus

(3) All oxoacids contain atleast one P = O unit and one P OH group

(4) Orthophosphoric acid is used in the manufacture of triple superphosphate

Ans. (1)

Sol.Hypophosphorous acid is a monoprotic acid


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[32]

198. In the extraction of copper from its sulphide ore the metal is finally obtained by the reduction of cuprousoxide with:

(1) Sulphur dioxide (SO2) (2) Iron sulphide (FeS)

(3) Carbon monoxide (CO) (4) Copper (I) sulphide (Cu2S)

Ans. (4)

Sol. 2 2 22Cu O Cu S 6Cu SO (Self reduction method)

199. Identify the alloy containing a non-metal as a constituent in it

(1) Steel (2) Bell metal (3) Bronze (4) Invar

Ans. (1)

Sol.Steel contains carbon as non metal constituent

200. 50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin holeunder the similar conditions. If molecular mass of gas B is 36, the molecular mass of gas A will be:

(1) 128 (2) 32 (3) 64 (4) 96

Ans.(No option is correct)

Sol.A B

B A

r M200r 150 M

A

4 3 6

3 M

A

9 36 81M 20.25

16 4

*****

cbse paper solutions 2012

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