Holiday Homework Class VIII Science

Q.1 Collect different types of seeds & put them in small bags.Attach these bags in a

herbarium file and label them. Q.2 Collect new agricultural machine pictures & paste in afile with their names & uses.

Q.3 Learn all the exercises & assignments questions of chapter crop production &

management.

Class IX Chemistry

Q.1 When 3.0g of carbon is burnt in 8.00g oxygen,11.00g of carbon dioxide is produced.

What mass of carbon dioxide will be formed when 3.00g of carbon is burnt in 50.00g of

oxygen? When law of chemical combination will govern your answer.

Q.2What are polyatomic ions ? Give examples.

Q,3State& explain law of conservation of mass.prove it with one example.

Q.4 Define law of constant proportion.Explain it with one example.

Q.5Write down the pastulates of Dalton’s atomic theory.

Q.6What is a atomicity.

Q.7 what is an ion ?Give five examples.

Q.8 Classify molecule on the basis of atomicity: C2H6, F2, P4H10,O3, co32-,He,H2O2,CO,NO2

Class X Chemistry

Q.1 Explain the nature of the covalent bond using the bond formation in CH3Cl.

Q.2 Draw the electron dot structure for a) F2 b) CO2 c) S8 d)H2 e)O2

f)N2 g)CH4 h)CH3Cl

Q.3 What type of bonding is present in carbon.

Q.4 What is allotrophy.Discuss different allotropes of carbon in detail.

Q.5Explain versatile nature of carbon.

HOLIDAY HOMEWORK

ClassXII Chemistry

Q.1Write down the name reactions:Named Reactions Of1)Haloalkanes and haloarenesFinkelstein Reaction

,Fittig Reaction, Friedel craft’s reaction, Swarts reaction ,Wurtzreaction,Wurtz-fitting reaction

2) Named Reactions of Alcohols, Phenols and Ethers

Dow’s Process ,Williamson synthesis, Kolbe’s Reaction, Reimer Tiemann Reaction.

3)Named Reactions of Aldehydes, Ketones and Carboxylic Acids

RosenmundReaction,Stephen Reaction, Etard Reaction ,Gatterman – Koch reaction,Wolf Kishner

Reduction,Aldol condensationClemmenson’s Reduction,Cross aldol condensation,Cannizzaro

reaction, Hell-Volhard-Zelinsky reaction

4) Named Reactions Of Amines

Hoffmann Ammonolysis reaction, Hoffmann bromamide degradation reaction, Gabriel phthalimide

synthesis,Carbylaminereaction ,Sandmeyerreaction,Gatterman reaction, Diazotisation, Coupling Reaction. SUBJECT – CHEMISTRY

CLASS – XII

Time allowed: 3:00 hours Maximum marks: 70

1. What are F-centres?

2. Which of the following is the most effective electrolyte in the coagulation of Fe2O3.H2O/Fe+3sol?

KCl, AlCl3, MgCl2, K4[Fe(CN)6]

3. In the following pair of halogen compounds, which compound undergoes faster SN1 reaction?

(a) (b)

4. Give the IUPAC name of the following compound:

5. Arrange the following in increasing order of basic strength:

C2H5NH2, (C2H5)2NH, (C2H5)3N, C6H5NH2

6. a) What is the role of ZnCl2 in a dry cell?

b) Predict the products of electrolysis in an aqueous solution of AgNO3

with silver electrodes.

7. a) What is the difference between order of a reaction and its molecularity.

b) Give one example of a pseudo first order reaction.

8. Indicate the steps in the preparation of K2Cr2O7 from chromite ore.

OR

Compare the chemistry of the actinides with that of lanthanides with reference to: (i) Electronic

configuration (ii) oxidation states

9. The following is not an appropriate reaction for the preparation of t-butyl ethyl ether.

(i) What would be the major product of this reaction?

(ii) Write a suitable reaction for the preparation of t-butyl ethyl ether

10. Write the mechanism of hydration of ethene to yield ethanol.

11. Silver forms ccplattice and X-ray studies of its crystals show that the

edge length of its unit cell is 408.6 pm. Calculate the density of silver

(Atomic mass = 107.9 u).

12. Conductivity of 0.00241 M acetic acid is 7.896 × 10–5Scm–1. Calculate

its molar conductivity. If Λm0for acetic acid is 390.5 Scm2mol–1,

what is its dissociation constant?

13. The following data were obtained during the first order thermal

decomposition of SO2Cl2 at a constant volume.

SO2Cl2 (g) SO2 (g) + Cl2 (g)

Experiment Time / s-1 Total pressure/ atm

1 0 0.5

2 100 0.6

Calculate the rate constant for the reaction.

14. a) What do you mean by selectivity of catalysts?

b) Why does physisorption decrease with the increase of temperature?

c) What is CMC?

15. a) What is the role of depressant in froth floatation process?

b) Why is zinc not extracted from zinc oxide through reduction using CO?

c) Outline the principle of zone refining.

16. Write balanced equations for the following:

a) White phosphorus is heated with concentrated NaOH solution in an

inert atmosphere of CO2.

b) Sulphur dioxide is passed through an aqueous solution of Fe(III) salt.

c) NaCl is heated with sulphuric acid in the presence of MnO2.

17. Give reasons:

a) Transition metals show variable oxidation states.

b) E0 for Mn+3/Mn+2 couple is more positive than that of Fe+3/Fe+2

c) Zn+2 salts are white while Cu+2 salts are blue.

18 a) What is ionisation isomerism .discuss by giving an example

b) Ambidentate ligand

OR

Compare following complexes w.r.t shape, magnetic behavior

[Ni(CO)4], [CoF6]3- , [Co(NH3)6]

3+

19. How will you bring about the following conversions in not more than two

steps?

(a) Propene to 1-nitropropane

(b) Ethanol to ethyl fluoride

(c) Benzene to biphenyl

20. a) Aniline does not undergo Friedel-Crafts reaction. Why?

b) Complete the following chemical equations:

(i) CH3CONH2 + Br2 + NaOH

(ii) C6H5N2Cl + C6H5OH

21. a) Define thermoplastics and thermosetting polymers with one example

of each.

b) Classify the following as addition and condensation polymers:

Terylene, Bakelite, Polyvinyl chloride, Polythene.

22. Explain the following with one suitable example:

a) Non-ionic detergents b) Food preservatives c) Disinfectants.

23. Nita’s mother fell ill and the doctor diagnosed her with pernicious

anemia.She felt lethargic and did not have the energy to do work. Nita

helped her mother in household work till she recovered.

a) Name the vitamin whose deficiency caused pernicious anemia.

b) Name the sources which will provide this vitamin.

c) Is this vitamin water-soluble or fat-soluble?

d) Mention the values shown by Nita.

24. a) What would be the value of Vant Hoff’s factor for a dilute solution of

K2SO4 in water?

b) When mercuric iodide is added to an aqueous solution of KI the

freezing point is raised. Why?

c) Vapour pressure of chloroform (CHCl3) and dichloromethane

(CH2Cl2) at 298 K are 200 mm Hg and 415 mm Hg respectively.

Calculate:

(i) the vapour pressure of the solution prepared by mixing

25.5 g of CHCl3 and 40 g of CH2Cl2 at 298 K and,

(ii) mole fractions of each component in vapour phase.

OR

a) A doctor advised a person suffering from high blood pressure to take less quantity of common salt.

Explain.

b) A and B liquids on mixing produce a warm solution. Which type of deviation from Raoult’s law is

there?

c) If N2 gas is bubbled through water at 293 K, how many millimoles of N2 gas would dissolve in 1 litre of

water. Assume that N2 exerts a partial pressure of 0.987 bar. Given that Henry’s law constant for N2

at 293 K is 76.48 kbar.

25. (i) Account for the following:

a) Nitrogen shows catenation properties less than Phosphorus.

b) Sulphur in the vapour state exhibit paramagnetism.

c) Bond dissociation enthalpy of fluorine is less than chlorine.

(ii) How are XeO3 and XeOF4 prepared?

OR

a) Name two poisonous gases which can be prepared from chlorine gas.

b) Write the conditions to maximize the yield of H2SO4 by Contact process.

c) How is O3 estimated quantitatively?

d) Draw the structure of pyrophosphoric acid.

e) Arrange the following in the order of increasing bond dissociation enthalpy.

F2, Cl2, Br2, I2

26. a) Give simple chemical tests to distinguish between the following pairs

of compounds:

(i) Phenol and Benzoic acid

(ii) Pentan-2-one and Pentan-3-one

b) Convert:

(i) Ethanol to 3-Hydroxybutanal

(ii) Benzaldehyde to benzophenone

c) pKa value of chloroacetic acid is lower than that of acetic acid. Why?

OR

a) Give one example of each of the following:

(i) Cannizzaro's reaction (ii) Hell VolhardZelinsky reaction

b) An organic compound (A) (molecular formula C8H16O2) was hydrolysed

with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol

(C).Oxidation of (C) with chromic acid produced (B). (C) on dehydration

gives but-1-ene. Write the names and structures of (A), (B) and(C)

Chemistry (Theory)

Time allowed:3 hours Maximum marks:70

1. What type of stoichiometric defect are found in ZnS ? 1

2. What is the effect of temperature on chemisorption? 1

3.What is the basicity of H3PO3? 14.Which would undergo SN1

reaction faster in the following pair and why ?

CH3-CH2-Br and CH3-CBr(CH3)-CH3 1

5.Write the IUPAC name of the given compound : 1

HO – CH2-CH(CH3)-CH2-OH

6.State Henry’s law. Why do gases always tend to be less soluble in liquid as the temperature is raised?

OR

State Raoult’s law for the solution containing volatile components. Write the one difference between an ideal

solution and a non ideal solution.

1+1

7.Statekohlrausch law of independent migration of ions. Why does conductivity of solution decrease with

dilution? 2

8.Draw the structure of following:

(i)XeF2 (ii)BrF3 2

9.(i)Out of white and red phosphorous which one is more reactive and why ?

(ii)what do mean by dispropotionationreaction?Give one example.

1+1

10. Write the equations involved in the following reaction:

(i) Cannizzaro reaction.

(ii) Hell-volhardzelinsky reaction. 1+1

11. Analysis shows that nickel oxide has the formula Ni .98O1.00.What fraction of nickel exist as Ni .2+

and

Ni.3+

ions ? 3

12.Calculate the mass of ascorbic acid (C6H8O6)to be dissolved in 75gm of acetic acid to lower its melting point

by 1.5oC. (Kf=3.9 K kg/mol.) 3

13. (a)Calculate ∆rG0 for the reaction :

Mg (s) + Cu2+

(aq) →Mg2+

(aq) + Cu(s)

Given: E0

cell = +2.71 V, 1F= 96500 C per mol

(b)Name the type of the cell which was used in Apollo space programme for providing electrical

power. 3

14 Explain what is observed :

(1) When a beam of light is passed through the colloidal solution.

(2) An electrolyte,NaCI is added to ferric hydroxide solution.

(3)Electric current is passed through a colloidal sol. 3

15 (a) Outline the principal of refining of metals by the following :

(1) Van Arkel process

(2) Zone refining

(b)What are depressants. 3

16. Account for the following :

(1)Zn is not considered as a transition element.

(2)Transition metals form a large no. of complexes.

(3)With reference to structural variability and chemical reactivity, write the difference between

lanthenoids and actinoids.

OR

(1)Name a member of lanthanoids series which is well known to exhibit +4 oxidation state.

(2)Complete the following equation:

MnO4-- + 8H

+ + 5e

-→

(3)Out of Mn3+

and Cr+3

, which is more paramagnetic and why?(atomic no. : Mn =25, Cr=24)

3

17 (a) Give IUPAC name of linkage isomer of [Co (NH3)5NO2]2+

(b) Discuss the hybridization and magnetic character in the following coordination entities on the

basis of valence bond theory :-

[Fe(CN)6]4-

, [CoF6]3-

3

18 Account for following :

(1) Alcohols are more soluble in water than hydrocarbons of comparable molecular masses.

(2) Ortho-nitro phenol is more acidic than ortho-methoxy phenol.

(3) Distinguish between propane -1-ol and propane -2-ol . 3

19.An organic compound with molecular formula C9H10O form 2,4-DNP derivative, reduce Tollen” reagent and

undergoes Cannizzaro

reaction. On vigorous oxidation ,it gives 1,2-benzenedicarboxylic acid. Identify compound. Give three chemical

reaction. 3

20. Account for the following :

(1) Primary amines (R−NH2) have higher boiling point than tertiary amines (R3N).

(2) Aniline does not undergo Friedel craft reaction.

(3) (CH3)2NH is more basic than (CH3)3N in an aqueous solution. 3

21. What are the differences between DNA and RNA(two structural and one functional difference). 3 22

Write the formula of the monomers of the following polymers :

(i) Nylon-6

(ii) Novolac

(iii) Buna –N 3

23. On the occasion of World Health Day,Dr. Agam organized a ‘health camp’ for the poor farmers living in

nearby village. After check up, he was shocked to see that most of the farmers suffered from cancer due to

regular exposure to pesticides and many were diabetic. They distributed free medicines to them. Dr.Agam

immediately reported the matter to the National Human Rights Commision (NHRC). On the suggestions of

NHRC,the government decided to provide medical care, financial assistance, setting up of super speciality

hospitals for treatment and prevention of the deadly disease in the affected villages all over India.

(1) Write the values shown by Dr.Agam.

(2) What type of analgesics are chiefly used for the relief of pains of terminal cancer?

(3) Give any two example of artificial sweetener that could have been recommended to diabetic

patients. 4

24. (a) Account for the following :

(i) Interhalogens are more reactive than pure halogens .

(ii) N2 is less reactive at room temperature .

(iii) Reducing character increases from NH3to BiH3.

(b)Draw the structures of the following :

(i)H4P2O7

(ii)H2S2O7

OR

(a)Which poisonous gas is evolved when white phosphorous is heated with conc.NaOHsol.?Write

the chemical equation involved.

(b)Which noble gas has lowest boiling point?

(c)Fluorine is a stronger oxidizing agent than chlorine. Why?

(d)What happens when H3PO3 is heated?

(e)Complete the equation:

PbS+O3→ 5

25.(a)what is rate of reaction? Write two factors on which rate of reaction depends.

(b) Rate constant of a first order reaction increases from 4x10-2

to 8 x10-2

when the temperature changes

from 270C to 37

0C.Calculate the energy of activation?

OR

(a) For a reaction A+B →P,The rate is given by

Rate=k[A][B]2

(i)How is rate is affected if the conc.of B is doubled?

(ii)What is overall order of reaction if the conc. of A is present in large excess?

(b) A first order reaction takes 23.1 min. for 50% completion. Calculate the time required for 75% completion

of this reaction. 5

26.(i) Out of HCI(g)and SOCI2which is preferred for converting ethanol into chloroethane?

(ii)Why is chloroform stored in dark coloured bottles?

(iii)Out of C6H5CH2CI and C6H5CHCIC6H5,which is more easily hydrolysed by aqueous KOH.

(iv)Explain why Alkyl halides give cyanides with KCN but isocyanides with AgCN as the products.

(v)Arrange the following in increasing order of boiling point:

Bromomethane,bromoform,chloromethane,dibromomethan

OR(A) Compound ‘A’ with molecular formula C4H9Br is treated with aq.KOH solution.

The rate of this reaction depends upon the concentration ’A’ only. When another optically active isomer ‘B’ of

this compound was treated with aq.KOH solution. The rate of reaction was found to be dependent on

concentration of compound and KOH both.

(i)Write down the structural formula of both compounds ‘A’ and ‘B’.

(ii) Out of these two compounds, which one will be converted to the product with inverted configuration.

(B)How the following conversions can be carried out ?

(i) Tert. butyl bromide to isobutyl bromide.

(ii) Benzene to 4- bromonitrobenzene. 5

OR

(a)Which poisonous gas is involved when white phosphorus is heated with cons. NaOHsolution ?

Write the chemical equation involved.

5

SECOND PREBOARD EXAMINATION

SUBJECT : CHEMISTRY

Time Allowed : Three Hours Max. Marks : 70

Q1. Write the structure of 2-bromo-2-methyl-3-secbutylheptane?

Q2. What are the physical states of dispersed phase and dispersion medium of Gels?

Q3. Write the balanced chemical equation for complete hydrolysis of XeF6?

Q4. Why do alkali metal halides not show frenkel defect?

Q5. What is the role of depressant in froth floatation process?

Q6. Define Van’t Hoff factor? Give its expression. What is the Van’t Hoff factor for a compound

which undergoes tetramerization in an organic solvent?

Q7. Why is the reduction of a metal oxide easier if the metal formed is in liquid state

at the temperature of reduction?

Q8. Describe the mechanism of the formation of diethyl ether from ethanol in the presence of

concentratedsulphuric acid.

OR

Compare the acidic nature b/w (i) Phenol and ethanol (ii) Phenol and carboxylic

Q9. Write the following reactions:

(I) AldolCondensation (ii) Gabriel Phthalimide Synthesis.

Q10. Calculate two third life of a reaction having k= 5.46 x 10-14 s-1 ?

Q11.Ethylene glycol (molar mass = 62 g mol¯1) is a common automobile antifreeze. Calculate the

freezing point of a solution containing 12.4g of this substance in 100 g of water. Would it be

advisable to keep this substance in the car radiator during summer?

Given :Kf for water = 1.86K kg/mol ,Kb for water = 0.512K kg/mol

Q12. An element X with an atomic mass of 60g/mol has density of 6.23g cm-3. If the edge

length of its cubic unit cell is 400 pm, identify the type of cubic unit cell. Calculate the radius of

an atom of this element.

Q13. The decomposition of N2O5 (g) is a first order reaction with a rate constant of 5 x 10-4 sec-1 at

45o C. i.e. 2N2O5(g)---4NO2 (g) + O2(g). If initial concentration o N2O5is 0.25M,calculate its

Concentration after 2 min. Also calculate half life for decomposition of N2O5(g).

Q14. Explain the following observations:

(a) Ferric hydroxide sol gets coagulated on addition of sodium chloride solution

(b) Cottrell’s smoke precipitator is fitted at the mouth of the chimney used in factories.

(c) Physical adsorption is multilayered, while chemisorption is monolayered.

Q15. Q26. Give reasons for the following:

(a) CN¯ ion is known but CP¯ ion is not known.

(b) NO2dimerises to form N2O4.

(c) ICl is more reactive than I2

Q16.(a) Give the IUPAC name of :

[Cr Cl2 (H2O)4] Cl

(b) Why do tetrahedral complexes not show Geometrical Isomerism?

(c) Differentiate between inner orbital and Outer Orbital Complexes.

Q17. (a) Which of the following two compounds would react faster by SN2 path way :

1 – bromobutane Or 2 - bromobutane and why.?

(b) Allyl chloride is more reactive than n - propyl chloride towards nucleophilic substitution

reaction. Explain why?

(c) Haloalkanes react with KCN to give alkyl cyanide as main product while with AgCN they

form

isocyanide as main product. Give reason.

Q18. Account for the following:

(a) Aspirin drug helps in the prevention of heart attack.

(b) Diabetic patients are advised to take artificial sweetners instead of natural sweetners.

(c) Detergents are non-biodegradable while soaps are biodegradable.

Q19. Write names of monomer/s of the following polymers and classify them as addition or

condensation polymers.

(a) Teflon

(b) Bakelite

(c) Natural Rubber

Q20. (a) What changes occur in the nature of egg proteins on boiling and where does water go?

(b) Name the type of bonding which stabilizes α -helix structure in proteins.

(c)What is the difference between fibrous and Globular proteins.

Q21. (a) Predict, giving reasons, the order of basicity of the primary , Secondary , tertiary methyl

Amines in the aqueous solution?

(b) Compare the basic nature of Aniline and Acetanilide.

OR

Account for the following:

(a) Aniline does not undergo Friedel Crafts alkylation

(b) Although – NH2 group is an ortho and para-directing group, nitration of aniline gives

alongwith

ortho&para-derivatives meta-derivative also.

(c) Draw the zwitter ion structure of sulphanillic acid.

Q22. Give the chemical reactions for the following :

(a) Catalytic reduction of butanal.

(b) Hydration of propene in the presence of dilute sulphuric acid.

(c) Reaction of propanone with methylmagnesium bromide followed by hydrolysis.

Q23. Sameer is a grade 10 student . He wishes to celebrate his 15th birthday with his friends .For

This he wanted to buy some balloons and fill these with a lighter than air gas. When they went

to

purchase the balloons, shopkeeper showed them two types of lighter gases which are used to fill

the balloons :hydrogen and Helium. Of these helium is Expensive. Kamal wanted to buy

hydrogen which was cheaper.

After reading the above passage, answer the following:

a) As a student of chemistry, why would you suggest Sameer to buy the expensive helium.Give

one reason.

b) Give one more use of helium connected with our daily life.

c) Give at least two reasons why is Helium very less reactive?

d) What are the any two values associated with above decision?

Q24.(a) Calculate the equilibrium constant for the reaction at 298K

Zn(s) + Cu2+(aq) ---------- Zn2+ (aq) + Cu(s)

Given E0(Zn2+/Zn) = -0.76V , E0(Cu2+/Cu) = =0.34V

(b) When a current of 0.75A is passed through a CuSO4 solution for 25 min, 0.369 g of copper is

deposited at the cathode. Calculate the atomic mass of copper.

OR

a) The conductivity of 0.20 M NaCl at 298 K is 0.0248 S cm-1.Calculate its molar conductivity.

b) Calculate the standard cell potential of the galvanic cell in which the following reaction is

taking place : 2 Cr(s) + 3 Cd2+(aq) ------- 2 Cr3+ + 3 Cd(s)

Given E0Cr3+/Cr= -0.74 V,E0Cd2+/Cd= - 0.40 V,1F=96500 C mol-1

c) Write the reactions involved in the working of lead storage battery.

Q25.(a) A blackish brown coloured solid ‘A’ when fused with alkali metal hydroxides in presence of

air, produces a dark green compound ‘B’, which on electrolytic oxidation in alkaline medium

gives a dark purple coloured compound C. Identify A, B and write the reactions involved.

b) What happens when an acidic solution of the green compound (B) is allowed to stand for

some time? Give the equation involved. What is this type of reaction called?

c) Why do transition compopunds form the complexes

OR

Give reasons for the following:

(a) Transition metals have high enthalpies of atomization.

(b) Among the lanthanoids, Ce(III) is easily oxidised to Ce(IV).

(c) What is the difference in the variability of oxidation states among p- block and d-block

elements.

(d) Copper (I) has d10configuration,while copper (II) has d9configuration, still copper (II) is more

stable in aqueous solution than copper (I).

(e) The second and third transition series elements have almost similar atomic radii.

Q26. Q28. (a) An organic compound ‘A’ with molecular formula C5H8O2 is reduced to n-pentane on

treatment with Zn-Hg/HCI. ‘A’ forms a dioxime with hydroxylamine and gives a positive

lodoform test and Tollen’s test. Identify the compound A and deduce its structure.

(b) Write the chemical equations for the following conversions:(not more than 2 steps)

(i) Acetic acid to Acetamide.

(ii) Aniline to phenol

(iii) Propanamide to Ethanamine.

OR

(a) An organic compound ‘A’ with molecular formula C8H8O gives positive DNP and iodoform

tests.

It does not reduce Tollen’s or fehling’s reagent and does not decolourise bromine water also.

On oxidation with chromic acid(H2CrO4), it gives a carboxylic acid (B) with molecular formula

C7H6O2. Deduce the structures of A and B. Give chemical reactions.

(b)There are two NH2 groups in semicarbazide but only one can react with carbonyl compounds?

(c)Why do Formaldehyde not show the aldol condensation reaction?

Chemistry (Theory)

Time allowed:3 hours Maximum marks:70

1. What type of stoichiometric defect are found in ZnS ? 1

2. What is the effect of temperature on chemisorption? 3.What is

the basicity of H3PO3? 4.Which would

undergo SN1 reaction faster in the following pair and why ?

CH3-CH2-Br and CH3-CBr(CH3)-CH3 1

5.Write the IUPAC name of the given compound : 1

HO – CH2-CH(CH3)-CH2-OH

6.State Henry’s law. Why do gases always tend to be less soluble in liquid as the temperature is

raised?

OR

State Raoult’s law for the solution containing volatile components. Write the one difference

between an ideal solution and a non ideal solution.

1+1

7.Statekohlrausch law of independent migration of ions. Why does conductivity of solution decrease

with dilution? 2

8.Draw the structure of following:

(i)XeF2 (ii)BrF3 2

9.(i)Write down the IUPAC name of the following complex :

[Co(NH3)5(NO2)](NO3)2

(ii) Write the formula for the following complex :

Potassium tetracyanidonickelate(II). 1+1

10. Write the equations involved in the following reaction:

(i) Cannizzaro reaction.

(ii) Hell-volhardzelinsky reaction. 1+1

11. Analysis shows that nickel oxide has the formula Ni .98O1.00.What fraction of nickel exist as Ni .2+

and

Ni.3+ions ? 3

12.Calculate the mass of ascorbic acid (C6H8O6)to be dissolved in 75gm of acetic acid to lower its

melting

point by 1.5oC. (Kf=3.9 K kg/mol.) 3

13. (a)Calculate ∆rG0 for the reaction :

Mg (s) + Cu2+(aq) →Mg2+(aq) + Cu(s)

Given: E0cell = +2.71 V, 1F= 96500 C per mol

(b)Name the type of the cell which was used in Apollo space programme for providing

electrical power.

3

14 Explain what is observed :

(3) When a beam of light is passed through the colloidal solution.

(4) An electrolyte,NaCI is added to ferric hydroxide solution.

(3)Electric current is passed through a colloidal sol.

3

15 (a) Outline the principal of refining of metals by the following :

(3) Van Arkel process

(4) Zone refining

(b)What are depressants.

3

16. Account for the following :

(1)Zn is not considered as a transition element.

(2)Transition metals form a large no. of complexes.

(3)With reference to structural variability and chemical reactivity, write the difference

between

lanthenoids and actinoids.

OR

(1)Name a member of lanthanoids series which is well known to exhibit +4 oxidation state.

(2)Complete the following equation:

MnO4-- + 8H+ + 5e-→

(3)Out of Mn3+ and Cr+3, which is more paramagnetic and why? (Atomic no. : Mn =25, Cr=24)

3

17 (a) Give IUPAC name of linkage isomer of [Co (NH3)5NO2]2+

(b) Discuss the hybridization and magnetic character in the following coordination entities on the

basis of valence bond theory :-

[Fe(CN)6]4-, [CoF6]

3- 3

18 Account for following :

(4) Alcohols are more soluble in water than hydrocarbons of comparable molecular masses.

(5) Ortho-nitro phenol is more acidic than ortho-methoxy phenol.

(6) Distinguish between propane -1-ol and propane -2-ol . 3

19.An organic compound with molecular formula C9H10O form 2,4-DNP derivative, reduce Tollen”

reagent and undergoes Cannizzaroreaction. On vigorous oxidation ,it gives 1,2-benzenedicarboxylic

acid. Identify compound. Give three chemical reaction. 3

20. Account for the following :

(1) Primary amines (R−NH2) have higher boiling point than tertiary amines (R3N).

(2) Aniline does not undergo Friedel craft reaction.

(3) (CH3)2NH is more basic than (CH3)3N in an aqueous solution. 3

21. What are the differences between DNA and RNA(two structural and one functional difference).

22 Write the formula of the monomers of the following polymers :

a. Nylon-6

b. Novolac

c. Buna –N 3

23. On the occasion of World Health Day,Dr. Agam organized a ‘health camp’ for the poor farmers

living in nearby village. After check up, he was shocked to see that most of the farmers suffered

from cancer due to regular exposure to pesticides and many were diabetic. They distributed free

medicines to them. Dr.Agam immediately reported the matter to the National Human Rights

Commision (NHRC). On the suggestions of NHRC,the government decided to provide medical care,

financial assistance, setting up of super speciality hospitals for treatment and prevention of the

deadly disease in the affected villages all over India.

(1) Write the values shown by Dr.Agam.

(2) What type of analgesics are chiefly used for the relief of pains of terminal cancer?

(3) Give any two example of artificial sweetener that could have been recommended to

diabetic Patients. 4

24. (a) Account for the following :(i) Interhalogens are more reactive than pure halogens .(ii) N2 is

less reactive at room temperature .

(iii) Reducing character increases from NH3to BiH3.

(b)Draw the structures of the following :

(i)H4P2O7

(ii)H2S2O7

OR

(a)Which poisonous gas is evolved when white phosphorous is heated with conc.NaOH

sol.?Write the chemical equation involved.

(b)Which noble gas has lowest boiling point?

(c)Fluorine is a stronger oxidizing agent than chlorine. Why?

(d)What happens when H3PO3 is heated?

(e)Complete the equation:

PbS+O3→ 5

25.(a)what is rate of reaction? Write two factors on which rate of reaction depends.

(b) Rate constant of a first order reaction increases from 4x10-2to 8 x10-2 when the temperature

changes from 270C to 370C.Calculate the energy of activation?

OR

(a) For a reaction A+B →P,The rate is given by

Rate=k[A][B]2

(i)How is rate is affected if the conc.of B is doubled?

(ii)What is overall order of reaction if the conc. of A is present in large excess?

(b) A first order reaction takes 23.1 min. for 50% completion. Calculate the time required for 75%

completion of this reaction. 5

26.(i) Out of HCI(g)and SOCI2which is preferred for converting ethanol into chloroethane?

(ii)Why is chloroform stored in dark coloured bottles?

(iii)Out of C6H5CH2CI and C6H5CHCIC6H5,which is more easily hydrolysed by aqueous KOH.

(iv)Explain why Alkyl halides give cyanides with KCN but isocyanides with AgCN as the products.

(v)Arrange the following in increasing order of boiling point:

Bromomethane,bromoform,chloromethane,dibromomethan

OR

(A) Compound ‘A’ with molecular formula C4H9Br is treated with aq.KOH solution. The rate of this

reaction depends upon the concentration ’A’ only. When another optically active isomer ‘B’ of this

compound was treated with aq.KOH solution. The rate of reaction was found to be dependent on

concentration of compound and KOH both.

(i)Write down the structural formula of both compounds ‘A’ and ‘B’.

(ii) Out of these two compounds, which one will be converted to the product with inverted

configuration.

(B)How the following conversions can be carried out ?

(iii) Tert. butyl bromide to isobutyl bromide.

(iv) Benzene to 4- bromonitrobenzene. 5

HOLIDAY HOMEWOK Class XI Chemistry

S.No. Name of Unit V.S.A.(1) S.A.(2) S.A.(3) V.B.(4) L.A.(5) Total

1 Some Basic Concepts of Chemistry 1(1) 2(4) 1(3) - - 4(8)

2 Structure of Atom - 1(2) 1(3) - 1(5) 3(10)

3 Classification of Elements and periodicity in properties 1(1) 1(2) 1(3) - - 3(6)

4 Chemical bonding and Molecular Structure 1(1) - 1(3) - 1(5) 3(9)

5 States of Matter: Gases and liquids - - 1(3) 1(4) - 2(7)

6 Thermodynamics - 1(2) 2(6) - - 3(8)

7 Equilibrium - - 1(3) - 1(5) 2(8)

8 Redox Reactions 1(1) - 2(6) - - 3(7)

9. Hydrogen 1(1) - 2(6) - - 3(7)

Total 5(5) 5(10) 12(36) 1(4) 3(15) 26(70)

Half Yearly Examination 2015-16

11th Chemistry Time Allowed:- 3 Question Paper M.M.:- 70 General Instructions

a. All questions are compulsory. b. Questions 1 to 5 are very short answer type questions and carry one mark each. c. Questions 6 to 10 carry two marks each. d. Questions 11 to 22 carry three marks each. e. Question 23 is value based carrying four marks. f. Questions 24 to 26 carry five marks each g. Use of calculators is not permitted. Use log table if necessary.

1. Write the Lewis dot symbol for NO2

- . 2. Write the IUPAC name and symbol for the element with atomic number 120. 3. Express the result of the given calculation to appropriate number of significant figures:

(3.24*0.08666)/5.006 4. Assign oxidation number to the underlined elements : (a) NaH2PO4 (b) NaBH4 5. Arrange NaH, H2O, MgH2 in increasing order of reducing property. 6. Calculate the concentration of nitric acid in moles per litre in a sample which has a density,

1.41 gmL-1 and mass percent of nitric acid in it being 69%. 7. Calculate the number of atoms in : (a) 52u of He (b) 52g of He 8. Calculate the wave number for the longest wavelength transition in the Balmer series of

atomic hydrogen. 9. How would you explain the fact that first ionization enthalpy of sodium is lower than that of

magnesium but its second ionization enthalpy is higher than that of magnesium? 10. Calculate the enthalpy change on freezing 1.0 mol of water at 10.0 oC to ice at -10.0 oC ,

fusH =6.03kJmol-1 at 0oC Cp[H2O(l)] = 73.5 Jmol-1K-1 Cp[H2O(s)] = 36.8 Jmol-1K-1

11. Calcium carbonate reacts with aqueous HCl according to the reaction: CaCO3(s) + 2HCl(aq)CaCl2(aq) + CO2(g) + H2O (l). What mass of CaCo3 is required to react completely with 25 mL of 0.75 M HCl?

12. (a) Write the electronic configuration of Copper.(1)

(b) Write two reasons for the stability of half filled and completely filled orbitals. (2) 13. (a) Explain why electron gain enthalpy of Fluorine is less than that of chlorine. (2) (b) Write the general electronic configuration of f-block elements.(1) 14. Describe the hybridization and structure of PCl5. Why are the axial bonds longer as compared to the equatorial bonds. 15. (a) 2.9 g of a gas at 95 oC occupied the same volume as 0.184 g of hydrogenat 17 oC at the

same pressure. What is the molar mass of the gas? (2) (b) Write the units of van der Waals parameters ‘a’ and ‘b’ . (1) 16. (a) Enthalpies of combustion of CO2 is -393.5 kJmol-1 . Calculate the heat released upon

formation of 35.2 g of CO2 from carbon and dioxygen gas. (2) (b) State first law of thermodynamics.(1)

17. Calculate the enthalpy of formation of CH3OH(l) From the following data: cH CH3OH(l) = -726 kJmol-1

cH C(s) = -393 kJmol-1 , cH H2(g) = -286 kJmol-1 18. (a) Derive relation between Kp and Kc .(2) (b)What is reaction quotient. (1) 19. Permanganate ion reacts with bromide ion in basic medium to give manganese dioxide and

bromate ion. Write the skeletal equation for the reaction and balance it by oxidation number method.

20. (a)Writing the equations for reactions taking place at anode and cathode predict the products of electrolysis of AgNO3(aq) with silver electrodes.(2)

(b) Name the indicator used in potassium dichromate redox titrations. (1) 21. (a) What is the difference between the terms hydrolysis and hydration? (1) (b) What are the causes of the temporary and permanent hardness of water? (2) 22. (a) Calculate the strength of 10 volume solution of hydrogen peroxide. (2) (b) Draw the structure of hydrogen peroxide in gas phase. (1) 23. In the month of December, Sunil filled air in the tyres of his car from the machine installed at

a petrol pump. He used to fill the same volume of air every time he visited petrol pump. However, when he filled the same volume of air in the month of June, there were frequent puncturing of tyres and sometimes there was leakage of air from the valves of the tyres. Sunil made a written complaint to the dealer of the car about this problem faced by him. Dealer politely advised Sunil to fill less quantity of air in the tyres in the summer season as compared to in the winter season to overcome this problem.

(i) Comment on the values displayed by the dealer of the car.(1) (ii) What concept of science is involved in the advice of the dealer?(2) (iii) What is absolute zero?(1) 24. (a) State the following (i) Aufbau Principle (ii) Pauli exclusion principle (iii) Hund’s rule of

maximum multiplicity. (b) How many electrons in an atom have the following quantum numbers (i) n = 4, ms = -1/2 (ii) n =3, l =0 (2)

OR (a) What are quantum numbers? Write the significance of each quantum number. (3) (b) Find the total number of protons in 34 mg of NH3 at STP ( Mass of proton= 1.6726*10-27

kg) 25. (a) Define the term Formal charge and calculate the formal charge on each oxygen atom in O3molecole(3) (b) Explain the geometry of SF4 molecule on the basis of VSEPR theory. (2)

OR (a) Draw the Energy level diagram for molecular orbitals of oxygen molecule and calculate

the bond order of the molecule. (2) (b) Compare the bond order, bond length and magnetic behavior of O2, O2

-, O2+ and O2

2- . (3)

26. (a) What will be the conjugate bases for : (i) HF (ii) HCO3- (1)

(b) Define the term ionic product of water. What is its value at 298 K. (2) (c) The concentration of hydrogen ions in a soft drink is 3.8 * 10-8 M. Calculate its pH. (2)

OR (a) Define the Le Chatelier’s Principle and discuss the effect of change in concentration and

temperature on the equilibrium. (3) (b) At a certain temperature and a total pressure of 105 Pa, iodine vapour contain 40% by

volume of iodine atoms [ I2 (g) 2I (g) ]. Calculate Kp for the equilibrium. (2)

Half Yearly Examination 2015-16

11th Chemistry Time Allowed:- 3 Question Paper M.M.:- 70 General Instructions

h. All questions are compulsory. i. Questions 1 to 5 are very short answer type questions and carry one mark each. j. Questions 6 to 10 carry two marks each. k. Questions 11 to 22 carry three marks each. l. Question 23 is value based carrying four marks. m. Questions 24 to 26 carry five marks each n. Use of calculators is not permitted. Use log table if necessary.

13. Write the Lewis dot symbol for NO2

- . 14. Write the IUPAC name and symbol for the element with atomic number 120. 15. Express the result of the given calculation to appropriate number of significant

figures: (3.24x0.08666)/5.006 16. Assign oxidation number to the underlined elements : (a) NaH2PO4 (b) NaBH4 17. Arrange NaH, H2O, MgH2 in increasing order of reducing property. 18. Calculate the concentration of nitric acid in moles per litre in a sample which has a

density, 1.41 gmL-1 and mass percent of nitric acid in it being 69%. 19. Calculate the number of atoms in : (a) 52u of He (b) 52g of He 20. Calculate the wave number for the longest wavelength transition in the Balmer

series of atomic hydrogen. 21. How would you explainthe fact that first ionization enthalpy of sodium is lower than

that of magnesium but its second ionization enthalpy is higher than that of magnesium?

22. A system absorbs 700 J of heat and does a work of 450 J, calculate the internal energy change of the system.

23. Calcium carbonate reacts with aqueous HCl according to the reaction: CaCO3(s) + 2HCl(aq)CaCl2(aq) + CO2(g) + H2O (l). What mass of CaCo3 is required to react completely with 25 mL of 0.75 M HCl?

24. (a) Write the electronic configuration of Copper.(1) (b) Write two reasons for the stability of half filled and completely filled orbitals. (2)

13. (a) Explain why electron gain enthalpy of Fluorine is less than that of chlorine. (2)

(b) Write the general electronic configuration of f-block elements.(1) 14. Describe the hybridization and structure of PCl5. Why are the axial bonds longer as compared to the equatorial bonds. 15. (a) 2.9 g of a gas at 95 oC occupied the same volume as 0.184 g of hydrogenat 17 oC

at the same pressure. What is the molar mass of the gas?(2) (b) Write the units of van der Waals parameters ‘a’ and ‘b’ . (1) 16. (a) Enthalpies of combustion of CO2is -393.5 kJmol-1 . Calculate the heat released upon

formation of 35.2 g of CO2 from carbon and dioxygen gas. (2) (b) State first law of thermodynamics.(1)

17. Calculate the enthalpy of formation of CH3OH(l) From the following data: cH CH3OH(l) = -726 kJmol-1

cH C(s) = -393 kJmol-1 , cH H2(g) = -286 kJmol-1 18. (a) Derive relation between Kp and Kc .(2) (b)What is reaction quotient. (1) 19. Permanganate ion reacts with bromide ion in basic medium to give manganese

dioxide and bromate ion. Write the skeletal equation for the reaction and balance it by oxidation number method.

20. (a)Writing the equations for reactions taking place at anode and cathode predict the products of electrolysis of AgNO3(aq) with silver electrodes.(2)

(b)Give one function of salt bridge (1) 21. (a) What is the difference between the terms hydrolysis and hydration? (1) (b) What are the causes of the temporary and permanent hardness of water? (2) 22. (a) Calculate the strength of 10 volume solution of hydrogen peroxide. (2) (b) Draw the structure of hydrogen peroxide in gas phase.(1) 23. In the month of December, Sunil filled air in the tyres of his car from the machine

installed at a petrol pump. He used to fill the same volume of air every time he visited petrol pump. However, when he filled the same volume of air in the month of June, there were frequent puncturing of tyres and sometimes there was leakage of air from the valves of the tyres. Sunil made a written complaint to the dealer of the car about this problem faced by him. Dealer politely advised Sunil to fill less quantity of air in the tyres in the summer season as compared to in the winter season to overcome this problem.

(i) Comment on the values displayed by the dealer of the car.(1) (ii) What concept of science is involved in the advice of the dealer?(2) (iii) What is absolute zero?(1) 24. (a) State the following (i) Aufbau Principle (ii) Pauli exclusion principle (iii) Hund’s

rule of maximum multiplicity. (b) How many electrons in an atom have the following quantum numbers (i) n = 4, ms = -1/2 (ii) n =3, l =0 (2)

OR (c) What are quantum numbers? Write the significance of each quantum number.

(3) (d) Find the total number of protons in 34 mg of NH3 at STP ( Mass of proton=

1.6726x10-27 kg) 25. (a) Define the term Formal charge and calculate the formal charge on each oxygen atom in O3molecole(3) (b) Explain the geometry of SF4 molecule on the basis of VSEPR theory. (2)

OR (c) Write the electronic configuration for molecular orbitals of nitrogen molecule

and calculate the bond order of the molecule. (2) (d) Compare the bond order, bond length and magnetic behavior of O2, O2

-, O2+ and

O22- . (3)

26. (a) What will be the conjugate bases for : (i) HF (ii) HCO3- (1)

(b) Define the term ionic product of water. What is its value at 298 K. (2) (c) The concentration of hydrogen ions in a soft drink is 3.8x 10-8 M. Calculate its pH. (2)

OR (c) Define the Le Chatelier’s Principle and discuss the effect of change in

concentration and temperature on the equilibriumreactionN2(g)+3H2(g)→ 2NH3(g). (3)

At a certain temperature and a total pressure of 105 Pa, iodine vapour contain 40% by

volume of iodine atoms [ I2 (g)2I (g) ]. Calculate Kp for the equilibrium. (2)

HALF YEARLY EXAMINATION

SUBJECT – CHEMISTRY

CLASS – XI

Time allowed: 3:00 hours Maximum marks: 70

1. State the modern periodic law.

2. Identify the species oxidised and reduced in the following redox reaction.

H2S (g) + Cl2 (g) → 2 HCl (g) + S (s)

3. What is the pH of our blood? Why does it remain constant inspite of the variety of

food and spices we eat?

4. Assign oxidation number to P in (i) NaH2PO4 (ii) H4P2O7

5. What is common ion effect?

6. Calculate the mass of an atom of carbon(C-12) in grams. Express the result up to

three significant figures.

7. Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are

polar.

8. a) For a reaction both ∆H and ∆S are positive. Under what conditions the reaction

occur spontaneously?

b) For the reaction, 2Cl (g) Cl2(g);

what are the signs of ∆H and ∆S ?

9. What do you understand by isoelectronic species? Name a species that will be

isoelectronic with each of the following:

(i) F– (ii) Ar

10. a) Draw the structure of hydrogen peroxide.

b) Hydrogen peroxide is used as a bleaching agent. Why?

OR Among NH3,

H2O and HF, which would you expect to have highest magnitude of hydrogen

bonding and why?

11. Define :

(i) Molarity (ii) Empirical formula (iii) Atomic mass

12. 3.0 g of H2 react with 29.0 g of O2 to form H2O.

(i) Which is the limiting reagent?

(ii) Calculate the maximum amount of H2O that can be formed?

(iii) Calculate the amount of the reactant left unreacted.

13. An electron has a speed of 500 m/s with uncertainty of 0.02%. What is the

uncertainty in locating its position?

14. Account for the following:

(i) Electron gain enthalpy of fluorine is less than that of chlorine.

(ii) First ionization enthalpy of boron is less than that of beryllium.

(iii) Lithium shows anomalous behaviour as compared to other group

members.

15. (a) Draw the Lewis structure of CO32- ion.

(b) Predict the shape of the following molecules using VSEPR model:

(i) NH3 (ii) H2O

16. What will be the pressure exerted by a mixture of 3.2 g of methane and 4.4 g of

carbon dioxide contained in a 9 dm3 flask at 270C ?

17. Explain the following terms:

a) Enthalpy of formation

b) State function

c) Gibbs free energy

18. (i) Write the general outer electronic configuration of d-block elements. (ii) Among

the elements of the third period- Na, Mg, Al, Si, P, S, Cl, Ar;

Pick out the element:

a) With the highest ionization enthalpy

b) With the largest atomic radius

c) That is the most reactive non-metal

d) That is the most reactive metal.

19. a) For the reaction: 2A(g) + 2B2(g) 2AB2(g), the equilibrium

constantKp at 270C is 4.0 What is the value of Kp for

(i) 2AB2 (g) 2A (g) + 2B2 (g)

(ii) A (g) + B2(g) AB2(g)

b) The value of Kc for the reaction: 2A B + C is 2 x 10-3 . At a

given time, the concentration of reaction mixture is [A] = [B] = [C] =

3 x 10-4 M. In which direction will the reaction proceed?

20. What is meant by hybridisation of atomic orbital? Give the shapes of sp, sp2, sp3 and

sp3d hybrid orbital.

21. What causes the temporary and permanent hardness of water? Discuss the method

of softening of hard water by synthetic ion exchange resins.

22. Balance the following chemical equations by oxidation number method or ion-

exchange method:

(i) MnO4–(aq) + Br–(aq) → MnO2(s) + BrO3

– (aq) (in basic medium)

(ii) Fe2+(aq) + Cr2O72– (aq) → Fe3+ (aq) + Cr3+(aq) (in acidic medium)

OR

a) What you mean by the term 'oxidation number'?

b) Depict the galvanic cell in which reaction

Zn(s) + 2Ag+ (aq) → Zn2+ (aq) +2Ag(s)

takes place. Further show:

(i) Which of the electrode is negatively charged,

(ii) The carriers of the current in the cell, and

(iii) Individual reaction at each electrode.

23. Rohit takes an open pan to cook vegetables and pulses at hill station, while Sohan

cooks pulses and vegetables in pressure cooker at the same place. The gas cylinder

of Rohit lasts for only fifteen days whereas Sohan uses one gas cylinder per month.

(i) Who will cook vegetables and pulses faster and why?

(ii) What is reason for delay in cooking by Rohit?

(iii) What value is possessed by Sohan?

(iv) Why does Sohan need only one gas cylinder per month and not two like

Rohit?

24. a) Differentiate between an orbit and an orbital.

b) The 4f subshell of an atom contains 10 electrons. What is the

maximum number of electrons having same spin in it?

c) What is the number of orbitals for n=3?

d) How many radial nodes are present in 3p orbitals?

e) What is the physical significance of square of ψ ?

OR

a) Write the electronic configuration of Cr+3ion.

b) What is Pauli's exclusion principle? Why is it called exclusion

principle?

c) Explain why exactly half-filled and completely filled orbitals are extra

stable?

25. a) Derive the relationship between Cp and Cv.

b) Calculate the standard enthalpy of formation of CH3OH(l)

from the following data:

(i) CH3OH(l) + 3/2 O2 (g) CO2(g) + 2H2O(l); ΔrH0 = -726 kJ/mol

(ii) C(graphite) + O2 (g) CO2 (g); ΔcH0 = -393 kJ/mol

(iii) H2 (g) + ½ O2 (g) H2O (l) ; ΔfH0 = -286 kJ/mol

OR

a) Explain why the entropy of a pure crystalline solid is zero at 0 K?

On which law is it based?

b) For the reaction 2 A (g) + B (g) → 2D (g), ΔU0 = –10.5 kJ and

ΔS0 = –44.1 J/K. Calculate ΔG0 for the reaction, and predict whether

the reaction may occur spontaneously or not?

26. a) What is solubility product of a salt? Find out the relationship between

the solubility and solubility product of CaF2.

b) Predict if the solutions of the following salts are neutral, acidic or

basic:

NaCl, KBr, NaCN, NH4NO3, NaNO2 and KF

OR

(i) Describe the effect of the following on the equilibrium of the reaction:

2H2 (g) + CO (g) CH3OH (g)

a) addition of H2 b) addition of CH3OH

c) removal of CO d) removal of CH3OH

(ii) What is meant by the conjugate acid-base pair? Find the conjugate

acid/base for the following species:

HNO2, CN–, HClO4 and S2–