junior chem 29-07-15 isomerisam holiday assignment

Isomerism

110. When light travels, it generates electromagnetic waves. Two figures are given below

I)

(This figure represents electro-magnetic waves of light oscillating in all planes passing through the direction shown in which light travels)

II)

(This figure represents electro-magnetic waves of light oscillating in only one planes passing through the direction shown in which light traveling)

Which of these two figures represents plane polarized light? (a) I (b) II (c) both (a) and (b) (d) None of these 111. A compound will be optically active if (a) It rotates the plane of polarization of ordinary light

(b) It rotates the plane of polarization of plane polarized light (c) both (a) and (b) (d) None of these

112. An optically active compound can be (a) Only dextro-rotatory (b) Only laevo-rotatory (c) Either dextro-rotatory or levo ratatory (d) Both dextro rotatory and laevorotatory 113. Which of the following statements about optical rotation is correct?

(a) A dextro-ratatory compound can be denoted by (d) or (+) while a laevo-ratatory compound can be denoted by (1) or (-). (b) A dextro-rotatory compound can be denoted by (d) or (-) while a laevo-rotatory compound

can be denoted by (1) or (+). (c) A dextrorotatory compound can be denoted by (1) or (+) while a laevorotatory compound can be denoted by (d) or (-). (d) Both (a) and (b)

114. An asymmetric centre is always

(a) 3sp - hybridized (b) 2sp hybridized (c) sp hybridized (d) None of these

115. An asymmetric carbon atom bears (a) All four identical groups or atoms (b) All four different groups or atoms (c) Two identical groups and two different groups (d) Three identical groups and one different groups 116. Which of the following compounds has asymmetric centre?

(a) 3 3

|

CH CH CH

Br

(b) 3 2 3

|

CH CH CH CH

Br

(c)

OH

(d)

OH

117. Which of the following compounds has asymmetric centre?

(a) 2 2

|

CH CH CH CH CH

Br

(b) Br (c) Br (d) Br

O

118. Which of the following compounds has asymmetric centre?

(a)

Br

(b) Br

O

(c) Br (d) both (b) and (c) 119. Which of the following compounds has asymmetric centre?

(a) OH

O O

(b) OHO

O

(c)

Br

(d) Br 120. Which of the following compounds has asymmetric centre?

(a)

C = C

H H

H CH

H D

C = C

H

Br (b) 2 2

3 3

| | |

CH C CH C CH

CH Br CH

(c)

2

|

CH C CH C CH

Br

(d) Both (a) and (c)

121. Which of the following compounds has two similar asymmetric centres?

(a) 3 2 3

| |

CH CH CH CH CH

Br Br

(b)

2 2

| | |

CH CH CH

Br Br Br

(c)

2 2

| | |

CH CH CH

I Br Br

(d)

3 3

| |

CH CH CH CH

Br Br

122. Which of the following compounds has two similar asymmetric centres?

(a)

Br

Br (b) Br Br (c)

Br

Br (d) Both (a) and (b) 123. Which of the following compounds has two similar asymmetric centres?

(a) Br

Br

(b)

Br

Br (c)

Br

Br (d) All of these 124. Which of the following compounds has two dissimilar asymmetric centres?

(a) 3 2 3| |

CH CH CH CH CH

Br Br

(b)

3 2

| | |

CH CH CH CH

Br Br Br

(c)

3 2

| |

CH CH CH CH

CI Br

(d) All of these

125. Which of the following compounds has two dissimilar asymmetric centres?

(a) Cl

Br

(b) Cl

Br

(c) Cl

Br

(d) Both (a) and (b) 126. Which of the following compounds has two dissimilar asymmetric centres?

(a) O O

(b)

O O

CH3 (c)

CH3

(d) Both (a) and (c) 127. Which of the following compounds has only two dissimilar asymmetric centres?

(a) (b) (c) Br

Cl

(d) All of these

128.

Br

ClCH - D

This molecule has one asymmetric centre. Which of the following presentations of this asymmetric centre is called wedge presentation?

(a)

Br

ClC

H

D (b)

Br

ClH D

(c) Both (a) and (b) (d) None of these

129.

Br CH - D

Cl This molecule has one asymmetric centre. Which of the following presentations of this asymmetric centre is called Fischer projection formula?

(a)

Br

ClC

H

D (b)

Br

ClH D


130.

Br

ClC

H

D About this presentation of asymmetric centre, which of the following statements is correct? (a) Br, Cl and C are on the paper (b) H is above while D is below the plane of paper (c) H is below while D is above the plane of paper (d) both (a) and (b)

131.

Br

ClH D

This presentation of asymmetric centre indicates which of the following spatial arrangements of the four atoms bonded with asymmetric centre?

(a)

C DH

Cl

Br

(b)

C DH

Cl

Br


132.

C DH

Cl

Br

About this presentation of asymmetric centre, which of the following statements is correct? (a) C is on the paper (a) C is on the paper (b) Br and Cl are below the plane of paper (c) H and D are above the plane of paper (d) All of these 133. 3

| |

CH CH CH

Br Cl

Which of the following presentations is a fischer projection formula of this molecule containing two asymmetric centres is correct?

(a)

CH3

CH3

Br

Cl

H

H

(b)

CH3

CH3

Br

Cl

H

H

(c) CH3

CH3

H

HBr

Cl (d) both (a) and (b)

134.

CH3

CH3

Br

Cl

H

H

This Fishcher projection formula represents which of the following spatial arrangements of atoms and groups present on both asymmetric centres?

(a)

C

C

CH3

CH3

Br

Cl

H

H

(b)

C

C

CH3

CH3

Br

Cl

H

H

(c)

C

C

CH3

CH3

Br

Cl

H

H

(d) None of these

135. 3 3| |

CH CH CH CH

Br Cl

Which of the following presentation is a sawhorse formula of this molecule containing two asymmetric centres?

(a)

CH3

CH3

Br

Cl

H

H

(b)

CH3

CH3

Br

ClH

H

(c) CH3

CH3

H

HBr

Cl (d) None of these

136. CH3

CH3

H

HBr

Cl In this presentation, for each line on the asymmetric centre is parallel to a line on the other asymmetric centre. Which of the following statements is true?

(a) The atoms or groups on two parallel lines are anti to each other. For example Br and Cl are projected anti (distant) to each other.

(b) The atoms or groups on two non-parallel lines are syn to each other. e.g H of Br- containing asymmetric centre and Cl of the other asymmetric centre are projected syn (closer) to each other. (c) Both (a) and (b) (d) None of these

137.

A

B

L M

Let the priority order (according to sequence rule) be 1 2 3 4A B L M This can be shown as

A1

B2

L3 M4

BottomLine

Which of the following steps or operations have to be done for obtaining R/S consfiguration of the asymmetric centre in this Fischer projection formula?

(a) Bring the least priority group on the bottom line by exchange with the group already present on the bottom line as

A1

B2

L3 M4

A1

B2L3

M4 (b) Do exchange between remaining pair of groups also is

A1

B2L3

M4

A1 B2

L3

M4 (c) Move from 1 to 3 via 2. If this movement is clockwise then configuration is R. And if this movement is anticlockwise then configuration is S as

A1 B2

L3

M4 Movement is anti-clockwise therefore, configuration is S. (d) All three steps (a),(b) and (c) are required which should be done in the order as first (a) then (b) then (c).

138. I)

CH3

H

H

OH

OH

CH3 II)

CH3

HO H

HHO

CH3 Which of the following statements is true about these molecules?

(a) I is a mesomer (b) I and II are identical (c) I and II are two different mesomers (d) Both (a) and (b)

139. I)

COOCH3COOH

H H II) COOCH3COOH

H H

III)

COOCH3 COOH

HH Which of the following statements is true about these molecules?

(a) I and II are a pair of enantiomers (b) II and III are identical (c) Both (a) and (b) (d) None of these

140. A molecule can be said to have plane of symmetry if (a) It can be divided into two equal halves - one half being the mirror image of the other half. (b) It can be divided into two halves - one half is not the mirror image of the other hals. (c) It does not have centre of symmetry. (d) It does not have axis of symmetry. 141. Which of the following compounds have plane of symmetry?

(a)

CH3

CH3

H

H OH

OH

(b)

CH3

CH3

H

H Br

OH

H Br

(c)

CH3

CH3 (d) All of these 142. Which of the following compounds have plane of symmetry?

(a)

Br

Br (b)

Br

Cl (c)

Br

Br (d)

Br

Br

O

143. Which of the following compounds have plane of symmetry?

(a) (b) (c) o o

(d) Both (a) and (c) 144. Which of the following compounds have plane of symmetry?

(a) CH3

H OH

COOH

(Lactic Acid) (b) COOCH3

H OH

COOH

H OH

(c) Both (a) and (b) (d) None of these 145. A molecule can have plane of symmetry if it has (a) Only one asymmetric centre (b) Two similar asymmetric centres (c) Two dissimilar asymmetric centres (d) None of these 146. Which of the following statements is true? (a) A molecule lacking plane of symmetry is often dissymmetric. (b) A dissymmetric molecule is always optically active. (c) Both (a) and (b) (d) None of these 147. A compound containing only one asymmetric carbon atom is (a) Always dissymmetric (b) Always optically active

(c) Both (a) and (b) (d) None of these 148. A compound containing two dissimilar asymmetric carbon atoms is (a) Always dissymmetric (b) Always optically active (c) Both (a) and (b) (d) None of these 149. A compound containing two similar asymmetric carbon atoms is (a) Always dissymmetric (b) Always optically active (c) Both (a) and (b) (d) None of these 150. Which of the following statements is correct for a molecule having two similar asymmetric carbon atom? (a) All optical isomers are optically active (b) All optical isomers are optically in active (c) One optical isomer is optically inactive and others are optically active (d) None of these 151. Which of the following statements correct about molecule containing two similar asymmetric

carbon atoms? (a) That optical isomer will be optically inactive in which configurations on both asymmetric centres are R (b) That optical isomer will be optically inactive in which configurations on both asymmetric centres are S (c) That optical isomer will be optically inactive in whichr configurations on one asymmetric centre is R while that on the other asymmetric centre is S. (d) Both (a) and (b)

152. Which of the following statements about molecules containing one or more asymmetric carbon atoms is correct?

(a) Two structures will be configurationally identical if they have same configurations on all respective asymmetric centres.

(b) Two structures will be configurationally identical if they have different configurations on all respective asymmetric centres.

(c) Two structures will be configurationally identical if they have same configurations on all respective asymmetric centres.

(d) None of these

153. I)

CH3

H Br

C2H5 II) CH3

H Br

C2H5

III)

CH3

H Br

C2H5

H Br

Which of these molecules is optically active? (a) I (b) II (c) III (d) All of these

154. I)

CH3

H Br

H Br

CH3 II)

CH3

H Br

HBr

CH3 (c)

CH3

H Br

CH3

H

H

Br

Br

Which of these molecules is optically active? (a) I (b) II (c) III (d) I and III

155. I)

OH

OH II)

Br

Br

Br+

III) CH3

CH3

Which of these molecules is optically active? (a) I (b) II (c) III (d) I and II

156. I) Br II)

NO2

NO2 III)

O

NO2

NO2 Which of following molecules is optically active? (a) I and II (b) I and III (c) II and III (d) All of these

157. I) H

H

H

H

H

CH3

OH

CH3

II) H

H

H

H

H

CH3

OH

CH3

III) OH Which of the following molecules is optically active? (a) I and II (b) I and III (c) II and III (d) All of these

158. I)

CH3

H Br

C2H5 CH3

H Br

C2H5

CH3

HBr

C2H5

Which of these structures represent configurationally identical molecules? (a) I and II (b) I and III (c) II and III (d) None of these

159. I) COOCH3

H OH

COOH

H OH

II)

COOCH3

H OH

COOH

H OH

III)

COOCH3

HHO

COOH

HO H

Which of the these structures represent configurationally indentical molecules? (a) I and II (b) I and III (c) II and III (d) None of these

160. I) CH3

C2H5

H OH

II)

OH

C2H5H

CH3

III) CH3

C2H5

HHO


161. I)

CH3

H Cl

C2H5

Br H

II)

CH3

H Cl

C2H5

BrH

III) CH3

CH3

H Br

Cl H


162. I)

O

CH3 CH3

H H

II)

O

CH3 CH3

HH III) O

CH3CH3

HH Which of the these structures represent configurationally indentical molecules? (a) I and II (b) I and III (c) II and III (d) None of these 163. Which of the following statements is correct?

(a) A dissymmetric molecule always has non-superimposable mirror image and this mirror image is a different optical isomer. Secondly, both such isomers are optically active.

(b) A symmetric molecule always has superimposable mirror image and this image is not a different optical isomer. Secondly, such molecule is always optically inactive.

(c) Both (a) and (b) (d) None of these 164. If a molecule has only one asymmetric centre then it will be (a) Always super-imposable on its mirror image (b) Always non- superimposable on its mirror image.

(c) Superimposable on its mirror image in one isomer and non-superimposable on its mirror image in other isomers

(d) Optically inactive 165. If a molecule has two dissimilar asymmetric centres then it will be (a) Always super-imposable on its mirror image. (b) Always non-superimposable on its mirror image

(c) Superimposable on its mirror image in one isomer and non-superimposable on its mirror image in other isomers (d) Optically inactive

166. If a molecule has two similar asymmetric centres then it will be (a) Always super-imposable on its mirror-image (b) Always non-superimposable on its mirror-image (c) Superimposable on its mirro-image in one isomer and non-super imposable on its mirror- image in other isomers. (d) None of these 167. The structure of one optical isomer and the structure of other optical isomer will be non-superimposable mirror

image of each other only if (a) They have opposite configurations on all respective asymmetric centres (b) They have same configurations on all respective asymmetric centres (c) Both (a) and (b) (d) None of these 168. Which of the following statements is true for molecules having two similar asymmetric centres? (a) The isomer having opposite configurations on the two similar asymmetric centres will have superimposable mirror image.

(b) The isomer having same configurations on the two similar asymmetric centres will have superimposable mirror image.


169. I)

CH3

Ph

H OHS

II)

CH3

Ph

HOHR

III) CH3

Ph

HHOS

Which of the following statements is true about these molecules? (a). I and II are nonsupermposable mirror image of each other (b). I and III are non-superimposable mirror image of each other (c). I and III are identical (d) Both (a) and (c)

170. I)

CH3

H BrS

H BrR

C2H5 II) CH3

H BrS

H BrR

C2H5

III)

CH3

H

BrH

Br

R

C2H5

R

Which of the following statement is true about these molecules? (a). I and II are nonsupermposable mirror image of each other (b). I and III are non-superimposable mirror image of each other (c). I and II are identical (d) Both (a) and (c)

171. I)

CH3

OHHH OH

CH3 II)

CH3

HHOHO H

CH3 III)

CH3

HHO

OHH

CH3 Which of the following statements is true about these molecules? (a) I and III are nonsupermposable mirror image of each other (b) I and II are superimposable mirror image of each other (c) I and II are identical (d) Both (b) and (c)

172.

Br

Br Which of the following structures is the superimposable mirror image of this compound?

(a)

Br

Br (b)

Br

Br (c)

Br

Br (d) None of these 173. Which of the following compounds can have superimposable mirror image?

(a)

H

Br

H

Br

(b)

H H

Br Br (c) H

Br Br

H (d) All of these 174. Which of the following compounds can have superimposable mirror image?

(a)

CH3

OHHH OH

CH3

OHH

(b)

CH3

HHOH OH

CH3

OHH

(c)

CH3

HBrH OH

CH3

OHH

(d) All of these 175. For an open chain molecule containing n number of asymmetric centres, number of optical

isomers will be

(a) 2n (b) 12n

(c) 2n (d) 2n or less then 2n in some cases

176. If an open chain molecule has one or two or more dissimilar asymmetric centres, number of optical isomers will be

(a) 2n (b) 12n (c) 12n (d) 2n 177. If an open chain molecule has two or more similar asymetric centres, number of optical isomers will be

(a) 2n (b) more than 2n (c) less than 2n (d) 2n 178. 3 2

|

CH CH CH CH

OH

How many geometrical and optical isomers are possible in this compounds? (a). 0,2 (b) 0, 3 (c) 2,0 (d) 2, 2 179. 3 2 3

| |

CH CH CH CH CH

OH OH

How many optical isomers are possible in this compounds? (a). 2 (b) 3 (c) 4 (d) 5 180. 3 3

| |

CH CH CH CH

OH OH

How many optical isomers are possible in this compounds? (a). 2 (b) 3 (c) 4 (d) 5

181. 3 3| | |

CH CH CH CH CH

OH OH OH

How many optical isomers are possible in this compounds? (a) 2 (b) 3 (c) 4 (d) 5

182.

Br

Br How many stereoisomers are possible in this compound? (a) 2 (b) 3 (c) 4 (d) 5

183.

Br

Cl How many stereoisomers are possible in this compound? (a) 2 (b) 3 (c) 4 (d) 5

184.

Br

Br How many stereoisomers are possible in this compound? (a) 2 (b) 3 (c) 4 (d) 5

185.

Br

Cl How many stereoisomers are possible in this compound? (a) 2 (b) 3 (c) 4 (d) 5 186. A pair of enantiomers are (a) A pair of nonsuperimposable mirror image of each other (b) A pair of superimposable mirror image of each other

(c) Always optically active-if one is dextrorotatory then other will be levorotatory by same magnitude

(d) Both (a) and (c) 187. Enantiomers have

(a) All physical properties same except their action on plane polarized light which is equal in magnitude but opposite in direction. (b) All Chemical properties same except when reagent is chiral. In that case, reactivity of enantiomers will be different (c) Both (a) and (b) (d) None of these

188. A pair of diastereomers are (a) A pair of such stereoisomers o which are not mirror image of each other (b) A pair of non-superimposabl more sie mirror image of each other (c) Always optically active (d) Both (a) and (c) 189. A pair of diastereomers can be (a) A pair of geometrical isomers (b) A pair of such optical isomers which are not mirror image of each other (c) Both (a) and (b) (d) None of these 190. A mesomer is the one (a) Which has superimposable mirror image (b) Which has two or more similar asymmetric centres (c) Which has opposite configuration on the similar asymmetric centres (d) All of these

191. A meso isomer is (a) Always optically active (b) Always optically inactive (c) Always more reactive than other optical isomers (d) Always less reactive than other optical isomers 192. Which of the following statements is correct? (a) All optically inactive compounds are called mesomers (b) All mesomers are optically inactive compounds (c) Both (a) and (b) (d) None of these 193. A racemic mixture is (a) Always equimolar mixture of a pair of enantiomers (b) Always equimolar mixture of a pair of diastereomers

(c) Always optically inactive (d) Both (a) and (c) 194. Which of the following statements is true?

(a) The properties of a racemic mixture are same as those of constituent enaantiomers in gas phase or liquid state or in solution (b) The properties of a racemic mixture are not same as those of constiuent enantiomers in solid state. (c) Both (a) and (b) (d) None of these

195. I)

CH3

C2H5

H

H

OH

OH

II)

CH3

C2H5

HO H

HHO

III)

CH3

C2H5

H OH

HHO

IV)

CH3

C2H5

H OH

HHO

Which of the following statements is true about these isomers?

(a) I and II is a pair of enantiomers (b) III and IV is a pair of enantiomers (c) II is the diastereomer of III and IV (d) All of these

196. I)

H

CH3

Cl

Ph

II)

H

CH3

Cl

Ph III)

H

CH3

Cl

Ph Which of the following statements is true about these compounds?

(a) I and II are a pair of enantiomers (b) I and III are identical (c) I and III are diastereomers (d) Both (a) and (b)

197. I)

Br

COOH

H

COOCH3

BrH

II)

Br

COOH

H

Br H

COOCH3 III)

Br

COOH

H

COOCH3BrH

Which of the following statements is true about these isomers?

(a) I and III are identical (b) I and II are a pair of enantiomers (c) II is the diastereomer of I and III (d) Both (b) and (c)

198. I)

BrH

CH3ClH

CH3 II)

C BrH

HC

Cl

CH3

CH3

III)

CBr H

HC

Cl

CH3

CH3

Which of the following statements is true about these compounds?

(a) I and III are identical (b) II and III are a pair of enantiomers (c) I and III are a pair of diastereomers (d) Both (a) and (b)

199. I) CH3

CH3

H

HBr

Cl II) CH3

CH3

H

HBr

Cl III) CH3

CH3

H

HBr

Cl Which of the following statements is true about these molecules?

(a) II is the diastereomer of I and III (b) I and III are a pair of enantiomers

(c) All three are optically active (d) All of these

200. I)

H

D Cl

Br

II)

H D

Cl Br III) H D

Cl Br

Which of the following statements is true about these molecules?

(a) I and III are identical (b) I and II are a pair of enantiomers (c) I and III are a pair of diastereomers (d) Both (a) and (b)

201. I) H CH3 II) H CH3 III)

H CH3 Which of the following statements is true about these molecules?

(a) I and II are a pair of enantiomers (b) III is the diastereomer of I and II (c) III is not stereoisomer of I and II (d) Both (a) and (c)

202. I)

O

H

Ph II)

O

H

Ph III)

O

H

Ph Which of the following statements is true about these molecules?

(a) I and II are a pair of enantiomers (b) III is the diastereomer of I and II (c) III is not stereoisomer of I and II (d) Both (a) and (c)

205. I)

CH3

H

H

OH

OH

H OH

CH3 II)

CH3

HHOH

OH

H OH

CH3 Which of the following statements is true about these molecules? (a) Only I is a mesomer (b) Only II is a mesomer (c) Both I and II are two different mesomers (d) I and II are identical

206. I)

O O

H H II)

O

OH

H

III) O O

H H

IV) O

OH

H

Which of the following statements is true about these molecules? (a) I is a mesomer (b) I and III are identical (c) II and IV are a pair of enantiomers (d) All of these

207. I)

CH3 CH3

H H

+Br

II)

CH3 CH3

H HBr

+ (c) CH3

CH3H

H

+Br

(d)

CH3

CH3H

H+Br

Which of the following statements is true about these molecules? (a) I is a mesomer (b) I and III are identical (c) II and IV are a pair of enantiomers (d) All of these 208. Which of the following pairs of compounds have same boiling point? (a) (+) Lactic acid and (-) Lactic acid (b) (+) Lactic acid and (+) Lactic acid (c) (-) Lactic acid and ( + ) Lactic acid (d) All of these 209. Which of the following pairs of compounds have same melting points? (a) (+) tartaric acid and (-) tartaric acid (b) (+) tartaric acid and ( + ) tartaric acid

(c) (-) tartaric acid and ( + ) tartaric acid (d) Both (b) and (c)

210. Which of the following pairs of compounds have same solubility in water? (a) (+) tartaric acid and (-) tartaric acid (b) (+) tartaric acid and ( + ) tartaric acid (c) (-) tartaric acid and ( + ) tartaric acid (d) Both (b) and (c)

211.

COOH

CH3

H D +

COOH

CH3

HD + CH3OHCH3OH

COOCH3

CH3

H D

COOCH3

CH3

HD

( 1 2K and K are the rate constant) Which of the following statements is correct?

(a) 1 2K K (b) 1 2K K (c) The products I and II are a pair of enantiomers (d) Both (a) and (c)

212.

COOH

CH3

H D +

CH3

HOH

O = C

CH3

H D

CH3

D

HO

D

COOH

CH3

D H +

CH3

H

D

O = C

CH3

D H

CH3

D

HO

HO

I II

( 1 2K and K are the rate constant) Which of the following statements is correct?

(a) 1 2K K (b) Products I and II are a pair of diastereomers (c) Products I and II are a pair of enantiomers (d) Both (a) and (b) 213. A mixture of enantiomers or a racemic mixture can be resolved (separated) by applying which of the following

techniques? (a) Fractional distillation (b) Fractional crystallization (c) Chiral chromatography (d) Both (b) and (c) 214. A recemic mixture can be resolved by applying which of the following techniques? (a) By growing suitable bacteria (b) By converting into a mixture of suitable diastereomers (c) Both (a) and (b) (d) None of these 215. For the resolution of a racimic mixture, fractional crystallization can help only if (a) Both enantiomers give crystals of similar shape. (b) Both enantiomers give crystals of different shapes. (c) Both (a) and (b) (d) None of these 216. For the resolution of a racemic mixture, convertion into a mixture of suitable diasteriomers helps because (a) Boiling points of diastereomers are always different (b) Boiling points of diastereomers are always same (c) Boiling points of diastereomers are same in some cases but different in other cases (d) Diastereomers have same reactivity with a chiral reagent

217. 3 3|

CH CH CH CH CH

OH

For the given structure, how many stereoisomers and how many racemic mixtures are possible? (a) 4,4 (b) 4,2 (c) 6,3 (d) 6,4

218. 3 3| |

CH CH CH CH CH CH

OH OH

For the given structure, how many stereoisomers and how many racemic mixtures are possible? (a) 4, 2 (b) 8, 6 (c) 8, 4 (d) 6, 3

219. 3 3|

CH CH CH CH CH CH CH

OH

For the given mixture, how many stereoisomers and how many racemic mixtures are possible? (a) 4, 2 (b) 8, 6 (c) 8, 4 (d) 16, 8

220. For the given structure, how many stereo isomers and how many recemic mixtures are possible?

(a) 2, 1 (b) 4, 2 (c) 6, 3 (d) 8, 4

221. For the given structure, how many stereo isomers and how many racemic mixtures are possible?

(a) 4, 2 (b) 8, 4 (c) 16, 8 (d) 2, 1

222.

OH

For the given structure, how many stereo isomers and how many racemic mixtures are possible?

(a) 2, 1 (b) 4, 2 (c) 8, 4 (d) 0, 0

223.

OH


(a) 2, 1 (b) 2, 0 (c) 4, 2 (d) 4, 0

224. OH OH

For the given structure, how many stereo isomers and how many racemic-mixtures are possible? (a) 2, 1 (b) 4, 2 (c) 4, 0 (d) 3, 0

225. OH Br


(a) 2, 1 (b) 4, 2 (c) 4, 0 (d) 3, 0

226. OH


(a) 2, 1 (b) 4, 2 (c) 4, 0 (d) 3, 0

227.

3 3

| |

CH CH CH CH CH CH

HO Br

A mixture of all stereoisomers possible from this structure is subjected to fractional distillation. Then how many fractions will be obtained?

(a) 2 (b) 4 (c) 6 (d) 7

228. 3 3| |

CH CH C C CH CH

OH Br

A mixture of all stereoisomers possible from this structure is subjected to fractional distillation. Then how many fractions will be obtained?

(a) 1 (b) 2 (c) 3 (d) 4

229. 3 3| |

CH CH C C CH CH

OH OH

A mixture of all stereoisomers possible from this structure is subjected to fractional distillation. Then how many fractions will be obtained? (a) Two fractions are obtained, each fraction contains a pair of enantiomers. (b) Two fractions are obtained, one fraction contains a single meso compound and the other fraction contains a pair of enantiomers. (c) Three fractions are obtained, each fraction contains a pair of enantiomers. (d) Three fractions are obtained, two fractions contain a single meso compound and one fraction contains a pair of enantiomers.

230.

O

Br

Br A mixture of all stereisomers possible from this structure is subjected to fractional distillation. Which of the following statements is correct? (a) Two fractions are obtained, each fraction contains a pair of enantiomers. (b) Two fractions are obtained, one fraction contains a pair of enantiomers. (c) Three fractions are obtained, each fraction contains a pair of enantiomers.

(d) Three fractions are obtained, two fractions contain a single meso compound and one fraction contains a pair of enantiomers.

231. Which of the following statement is correct about retention / invertion of configuration during the course of a reaction? (a) Configuration is retained if reagent attacks from the same side of leaving group. (b) Configuration is inverted if reagent attacks from the backside of leaving group.

(c) No change in configuration is possible if any bond the asymmetric centre is not cleaved during the course of reaction.

(d) All of these

232.

CH3

BrH

C2H5

S

CH3

HHO

C2H5

R

OH

I

CH3

BrD

C2H5

S

CH3

HHO

C2H5

R

1. Mg 2. H2O

II Which of the following statements is true about these two reactions? (a) Both reactions lead to retention of configuration. (b) Both reactions lead to inversion of configuration.

(c) First reaction leads to inversion of configuration while second reaction leads to retention of configuration. (d) First reaction leads to retention of configuration while second reaction leads to inversion of configuration.

233.

CH3

BrH

Ph

NH3

CH3

NH2 +H

Ph

H2N

CH3

H

Ph

50% 50% How much recemization is occurring in this reaction? (a) 0% (b) 50% (c) 100% (d) 70%

234.

CH3

BrH

Ph

CH3

NH2 +H

Ph

H2N

CH3

H

Ph

30% 70%

NH3

How much recemization is occurring in this condition? (a) 0% (b) 30% (c) 60% (d) 40%

235.

CHO

CH2 OH

H OH

CHO

CH2 OH

HOH

(+) Glyceraldehyde ( -) Glyceraldehyde

Which of the following statements is true about assigning D/L configuration to the asymmetric centre in the given compound? (a) Glyceraldehyde can be used as a reference compound. (b) (+) Glyceraldehyde is assigned D-con-figuration and (-) Glyceraldehyde is assigned L-configuration. This assignment is purely arbitrary. (c) One can attempt to prepare the given compound from glyceraldehydes. If it is prepared from D-glyceraldehyde then its configuration is D. But, if it is prepared from L-glyceraldehyde itself from the given compound. If the compound gives D-glyceraldehyde then it has D- configuration and if it gives L-glyceraldehyde then its configuration is L. (d) All of these

236.

COOH

OH

H CH2

CH2OH

CHO

H OH

(-) Isoserine (-) Glyceraldehyde

COOH

HHO

CH2OH(-) Glyceric acid

I

III

Based on these reactions and taking help from question 386, assign D/L configurations to the asymmetric centres in these compounds I , II and III. In this regard, which of the following choices is correct? (a) D, D, D (b) L, L, L (c) L, D, L (d) L, L, D

237. Which of the following statements is true about D/ L configuration?

(a) A compound with D- configuration to its asymmetric centre is always dextrorotatory and a compound with L-configuration to its asymmetric centre is always leverotaroty (b) A compound with D-configuration to its asymmetric centre is always levorotatory and a compound with L-configuration to its asymmetric centre is always levorotatory.

(c) A compound with D-configuration to its asymmetric centre can be either dextrorotatory or levorotatory and a compound with L-configuration can also be either dextrorotatory or levorotatoary (d) None of these 238. Which of the following statements is true for erythro / threo nomenclature of optical isomers? (a) It is possible if molecule has two dissimilar asymmetric centres containing two identical groups. (b) It is possible if molecule has two dissimilar asymmetric centres containing one identical groups. (c) That isomer is called erythro isomer in which identical groups are one the same side in Fischer projection formula. And if they are on opposite sides then it is called threo isomer. (d) Both (a) and (c) 239. In which of the following cases, is erythro threo nomenclature possible?

(a) 3 2 5

| |

CH CH CH C H

OH OH

(b)

3 2 5

| |

CH CH CH C H

OH Br


240. I)

CH3

Ph

H

H

OH

OH

II)

CH3

Ph

HHO

HO H

III)

CH3

Ph

HHO

H OH

IV)

CH3

Ph

HHO

H OH

Which of the following statements is true about these compounds? (a) I and II are erythro-dl-pair while III and IV are threo-dl-pair (b) I and III are threo-dl-pair while III and IV are erythro-dl-pair (c) I and IV are erythro isomers while II and III are threo isomers (d) I and IV are threo isomers while II and IV are erythro isomers

241. I) C2H5

H

Ph

H

CH3

Ph

II) C2H5

H

Ph

H

CH3

Ph

In terms of erythro / threo, these compounds can be named as (a) Both are erythro isomers (b) Both are threo isomers (c) I is erythro isomer while II is threo isomer (d) I is threo isomer while II is erythro isomer

242. A carbon atom is called pseudoasymmetric centre if (a) It is asymmetric in one isomer but not asymmetric in other isomer (b) It is not asymmetric in all isomers (c) It is asymmetric in all isomers. (d) None of these 243. Which of the following compounds has pseudoasymmetric centre?

(a) 3 3| | |

CH CH CH CH CH

OH OH OH

(b) 3 3| | |

CH CH CH CH CH

OH Br OH

(c)

OCH3 CH3

CH3 (d) All of these

244.

1 2 3 4 5

3 3

| | |

CH CH CH CH CH

OH OH OH

In which of the following isomers of this compound, C 3 is asymmetric?

(a)

CH3

H OH

H OH

OHHS

RCH3 (b)

CH3

HO H

H OH

OHHS

RCH3 (c)

CH3

HH

OH

OHHS

SCH3

H

(d) Both (a) and (b)

245.

1 2 3 4 5

3 3

| | |

CH CH CH CH CH

OH OH OH

In which of the following isomers of this compound, C-3 is not asymmetric?

(a)

CH3

H OH

H OH

OHHS

RCH3 (b)

CH3

HO H

H OH

OHHS

SCH3 (c)

CH3

H

H OH

HHOR

RCH3

HO

(d) Both (b) and (c) 246. In which of the following compounds, nitrogen atom is asymmetric?

(a) 3 2 3CH NH CH CH (b)

N

H

O

(c) 3 2 3

3

|

CH N CH CH

CD

(d) All of these

247. 3 2 3|

CH CH CH CH

OH

(2-Butanol)

3 2 3CH NH CH CH

(N Methylethanamine) 2 Butanol is optically active because it has one asymmetric carbon atom, but N- methylethanamine is not optically active even when it has an asymmetric nitrogen atom. This is because (a) ( + ) 2 Butanol can be resolved but ( + ) N-methylethanamine cannot be resolved (b) ( + ) 2 Butanol as well as ( + ) N-methylethanamine cannot be resolved (c) ( + ) 2 Butanol cannot be resolved but ( + ) N-methylethanamine can be resolved (d) ( + ) 2 Butanol as well as ( + ) N-methylethanamine can be resolved

248. Mixture of enantiomers of N-methylethanamine cannot be resolved due to (a) Pyramidal inversion which leads to rapid inter-conversion between the enantiomers of this compound as (b) Self deprotonation-protonation as (c) Both (a) and (b) (d) None of these 249. Which of the following compounds contain asymmetric S atom and thus optically active?

(a)

3 2 5

||

O

CH S C H

(b)

3 2 5

||

O

CH S OC H

(c)

3

||

O

CH O S OEt

(d) All of these

250. Which of the following conditions is required for a comulene to exhibit optical activity every though cumulenes do not have any asymmetric centre?

(a) There should be even number of continuous C = C bonds (b) Each terminal of cumulene must bear two different atoms of groups (c) There should be odd number of continuous C = C bonds and each terminal should bear two different atoms or

groups (d) Both (a) and (b) 251. Which of the following cumulenes is optically active? (a)

3 2CH CH C CH (b) 3 3CH CH C CH CH

(c) 3 3CH CH C C CH CH (d)

3

|

CH CH C C C Br

Cl

252. 3 3CH CH C CH CH

If this compound is optically active then it should be due to (a) Non planar geometry as

CH3

H

CH3

H

C = C = C

This geometry makes it dissymetric (b) Planar geometry as

CH3

H H

C = C = C

CH3

This geometry makes it dissymmetric (c) Non-planar geometry as

CH3 CH3

H

C = C = C

H This geometry makes it dissymmetric (d) None of these 253.

3 3CH CH C C C CH CH

This structure leads to how many optical isomers (a) 0 (b) 1 (c) 2 (d) 3 254. A biphenyl will be optically active if (a) Both phenyl rings are not coplanar to each other and either ring is not symmetrically substituted (b) Both phenyl rings are coplanar to each other and either ring is not symmetrically substituted (c) Both (a) and (b) (c) None of these 255. Which of the following biphenyls is optically active?

(a)

NO2

I (b)

I

IBrBr

(c)

I I

BrBr

(d)

I I

BrBr

Br

I

256. Which of the following compounds is optically active?

(a)

CH - CH3

CH3 (b)

CH - Me

Me (c)

CH - CH3

CH3

(d) All of these 257. Which of the following compounds is optically active?

(a)

CH3

CH3 (b)

CH - Me

CH - Me (c)

CH3

CH3 (d) Both (a) and (c)

258. Which of the following compounds optically inactive but exhibits geometrical isomerism?

(a)

CH - Me

CH - Me (b) CH3 CH3

(c) Both (a) and (b) (d) None of these 259. If C is the concentration of an optically active compound, l is the length of polarimeter-sample-tube, -(obs) is

observed rotation and [ ] is the specific rotation, then which of the following equations can be applied to find the optical activity of a compound?

(a) ( )

[ ].

obs

c l

(b)

( )[ ]

obs

c l

(c)

( )[ ]

obs

c l

(d) None of these

260. Which of the following statements is true for applying above equation to measure the optical activity of a compound? (a) Unit of concentration should be gm/ml and that of length should be dm (b) Unit of concentration should be mg/ml and that of length should be cm (c) Any unit ;of concentration and length can be used (d) None of these 261. If 1 = 1 dm and c = 1 gm/ml then specific rotation of the compound should be:

(a) ( )obs (b) 2 ( )obs (c) 12 ( )obs (d) None of these

262. If specific rotation of a compound is +030 and observed rotation ( )obs of the given sample of that compound is

04.05 , then which of the following effects will be observed on changing the concentration and length?

(a) Doubling the concentration of the compound will give 0[ ] 60 and ( )obs = 08.1 .

(b) Doubling the concentration of the compound will give 0[ ] 30 and ( )obs = 08.1

(c) Doubling the length of the sample tube will give 0[ ] 30 and ( )obs = 08.1

(d) Both (b) and (c) 263. Magnitude of specific rotation of a compound is independent of (a) Solvent (b) Concentration (c) Length of the sample tube (d) Both (b) and (c) 264. 0.5 gm of a compound was dissolved in 10 ml of a solvent. Optical rotation of the solution was measured to be +

01.5 at 025 C using a polarimeter tube of 1 dm length. Then which of the following will be the specific rotation of the enantiomer of this compound?

(a) 030 (b) 030 (c) 03 (d) 03

265. % optical purity of a sample containing two enantiomers can be expressed by?

(a) ( )

100[ ]

obs

(b)

2 ( )100

[ ]

obs

(c)

( )100

2[ ]

obs

(d) None of these

266. The observed optical rotation of a sample containing two enantiomers is found to be 12o and the specific rotation

of the dextro-isomer is 24o . Both observed and specific rotations are measured under identical conditions. Then optical purity and % composition of the sample will be

(a) Optical purity = 50%; the mixture contains 75% dextro-isomer and 25% laevo isomer. (b) Optical purity = 50%; the mixture contains 25% dextro-isomer and 75% laevo isomer. (c) Optical purity = 50%; the mixture contains 50% dextro isomer and 50% laevo isomer. (d) Opical purity = 70%, the mixture contains 85% dextro isomer and 15% laevo isomer.

267. Which of the following structures is the Newman projection formula of ethane?

(a)

H

H H

H

H

H

(b) H HH H

HH

(c) Both (a) and (b) (d) None of these 268. Which of the following structures of ethane is called staggered formula?

(a)

H

H H

H

H

H

(b) H HH H

HH

(c) Both (a) and (b) (d) None of these 269. Which of the following structures of ethane is called eclipsed formula?

(a)

H

H H

H

H

H

(b) H HH H

HH


270.

H

H H

H

H HH H

HH

H

H

3 3CH CH

These two are the Newman projection formula one staggered and other eclipsed of ethane. Now holding C-1 in hand and rotating C-2 unit by which of the following angles will give eclipsed from staggered and staggered from eclipsed?

(a) 30o (b) 60o (c) 90o (d) 100o

271.

H

C2H5F Cl

Br

CH3

This is the Newman projection formula of (a) 2 Bromo 3 chloro 2 fluoropentane (b) 3 Bromo 2 chloro 3 fluoropentane (c) 3 Bromo 2 chloro 2 fluoropentane (d) 2 Bromo 2 chloro 2 fluoropentane

272.

H

H

H

H

H

HHH Which of the following statements is true about this structure? (a) This is a Newman projection formula (staggered) of cyclopentane (b) This is a Newman projection formula (eclipsed) of cyclopentane (c) This is a Newman projection formula (staggered) of cyclohexane (d) This is a Newman projection formula (staggered) of Cyclobutane

273.

H

H

H

H HH

H

H Which of the following statements is true about this structure? (a) This is a Newman projection formula (staggered) of cyclohexane (b) This is a Newman projection formula (eclipsed) of cyclohexane (c) This is a Newman projection formula (eclipsed) of cyclopentane (d) This is a Newman projection formula (eclipsed) of cyclobutane 274. Which of the following statements is true about dihedral angles? (a) Dihedral angle is the angle between two planes defined by four atoms. (b) Dihedral angle is the angle between two planes defined by three atoms. (c) Both (a) and (b) (d) None of these 275. Which of the following molecules has dihedral angles?

(a) 3CH Cl (b)

CH2

Br

Cl (c) 3NH (d) 3 2CH NH

276. Cl Br

H F D

T In this structure, F-C-C-T and H-C-C-F dihedral angles are respectively?

(a) 0 0180 ,60 (b) 0 090 ,30 (c) 0 00 ,30 (d) 0 0180 ,120

277. Cl Br

H F

D

T In this structure, F-C-C-T and D-C-C-F dihedral angles are respectively?

(a) 120 ,0o o (b) 0 ,120o o (c) 160 ,10o o (d) 140 , 20o o 278. Which of the following conditions is required to exhibit conformational isomerism? (a) Molecule must have at least one unit of dihedral angle and there should be free rotation about a bond changing

the dihedral angle (b) Molecule must have at least one unit of dihedral angle and it should not be possible to change the dihedral angle

by free rotation about a bond.

(c) Molecule must have only 2sp -hybridized atoms

(d) None of these 279. Number of which of the following isomers is always infinite? (a) Geometrical isomers (b) Optical isomers (c) Conformational isomers (d) Structural isomers 280. Which of the following statements about conformers is correct? (a) Conformers exist in a state of dynamic equilibrium (b) At equilibrium, population of more stable conformers will be more than that of less stable conformer (c) Conformers cannot be separated (d) All of these 281. Which of the following compounds will exhibit conformational isomerism?

(a) 2H O (b) 2CH O (c) 4CH (d) None of these 282. Which of the following compounds will exhibit conformational isomerism?

(a) 2 2CH CH (b) 3NH (c) 3CH Cl (d) All of these

283. Which of the following compounds will exhibit conformational isomerism?

(a) 3CH OH (b) 2NH OH (c) 3 3CH CH (d) All of these 284. Which of the following compounds will exhibit conformational isomerism?

(a) 2 2CH C CH (b) (c) (d) All of these 285. Which of the following compounds will exhibit conformational isomerism?

(a) 3 2 3CH CH CH (b) 3 2 2 3CH CH CH CH

(c) 3 3

3

|

CH CH CH

CH

(d) All of these

286. Which of the following causes is correct to develope torsional strain in the molecule? (a) Bond pair bond pair repulsion (b) Steric repulsion (c) Vander Waals repulsion (d) Dipole dipole repulsion

287. I) H H

H

H

H

H

II) H H

H

H

H

H

(Staggered) (Eclipsed) These are the two important conformers of ethane. Which of these two structures has torsional strain? (a) I (b) II (c) both (a) and (b) (d) None of these

288.

H

H H

H

H HH H

HH

H

H

I(Staggered)

II(Eclipsed)

These two conformers exist in a state of dynamic equilibrium. Which one is more stable? (a) I (b) II (c) Both are equally stable (d) It is not possible to compare them for stability 289. Which of the following conformers of n-butane is most stable?

(a)

H

CH3H H

H

CH3

(b) H H

HCH3

CH3

H (c) H H

H

CH3

CH3

H (d) H H

CH3 CH3

H H

290. Which of the following conformers of n-butane is least stable?

(a)

H

CH3H H

H

CH3

(b) H H

H CH3

CH3

H (c) H H

H

CH3

CH3

H (d) H H

CH3 CH3

H H

291. Which of the following conformers of n-butane has torsional strain?

(a) H H

HCH3

CH3

H (b) H H

CH3CH3

H H (c) H H

H

CH3

CH3

H (d) Both (b) and (c)

292. I)

H H

H

(Gauche form)

CH3

CH3

H

II) H H

(Fully eclipsed form)

CH3CH3

H H

Among these conformers, the order of the magnitude of steric repulsion is (a) I > II > III (b) III > II > I (c) II > III > I (d) II > I > III 293. Which of the following plots is correct for potential energy of ethane as a function of rotation about C C bond?

(a) 0o 120

o180o 240

o

(Staggered)

(eclipsed)

P.E

Degree of Rotation

(eclipsed)

(Staggered) (Staggered)

(b) 0o 60o 120o 180o 240o 300o 360o

P.E

(Staggered)(Staggered)

(Staggered)

(Staggered)

(eclipsed)

(eclipsed)(eclipsed)

Degree of Rotation (c) Both (a) and (b) (d) None of these 294. Which of the following plots is correct for potential energy of n-butane as a function of rotation about C2-C3 bond?

(a)

0o 60o 120o 180o 240o 300o 360o

(Anti form)(Gauche) (Gauche) (Anti form)

(Partially eclipsed) (Partially eclipsed)

(Fully eclipsed)

P.E

Rotation angle (b)

0o 60o 120o 180o 240o 300o 360o

(Anti form)

(Gauche) (Gauche)

(Anti form)

(Partially eclipsed) (Partially eclipsed)

(Fully eclipsed)

P.E

Rotation angle (c) Both (a) and (b) (d) None of these

295. Which of the following conformers of 2-fluoroethanol is most stable?

(a)

H

H

F

OH

H

H

(Anti form) (b)

H

F

H

O-H

H

H

(Gauche form) (c)

H

F

H

OH

H

(Fully eclipsed form)

H

(d)

HH

OH

H

H

(Partally eclipsed form)

F

296. Which of the following statements is true about these two structures?

I) H

DCH3

Br

Cl

CH3

II)

H

D CH3

Br

CH3

Cl

(a) I and II are a pair of enantiomers (b) I and II are a pair of diastereomers (c) I and II are a pair of conformers (d) I and II are a pair of structural isomers

297. I)

1 COOH

CH3

HH

BrCl

2

3

180o II)

1 COOH

CH3

HHBr

Cl

2

34

Holding C-2 unit of I in hand, rotation of C-3 unit about C2-C3 bond by 180o seems to produce II. Which of the following statements is correct?

(a) I and II are a pair of enantiomers (b) I and II are a pair of diastereomers (c) I and II are a pair of conformers (d) I and II are identical

298. H

HH

H

H

H

(Staggered) Translating this staggered Newman projection formula of ethane into sawhorse projection appears as

(a)

H

HH

H

H

H

(b)

H

H

H

H

H

H


299. HH

HH

H H

Translating this eclipsed Newman projection formula of ethane into sawhorse projection appears as

(a)

H

HH

H

H

H

(b)

H

HH

H

H

H

(c) both (a) and (b) (d) None of these

300. Br

BrH

H

CH3

CH3

Translating this staggered Newman projection formula of 2,3 dibromobutane into staggered sawhorse projection

appears as

(a)

CH3

CH3H

H

Br

Br

(b)

CH3

CH3H

H

Br

Br

(c)

CH3

CH3H

H

Br

Br

(d) All of these

301. BrBr

HH

CH3CH3

Translating this eclipsed Newman projection formula of 2,3 dibromobutane into eclipsed sawhorse projection appears as

(a) CH3CH3

H HBr Br

(b) CH3CH3

H HBr Br

(c) CH3CH3

H Br Br H

(d)

CH3CH3H

Br Br

H

302. I)

CH3

CH3H

H

Br

Br

II) CH3CH3

H HBr Br

I and II are (a) A pair of optical isomers (b) A pair of conformers (c) A pair of geometrical isomers (d) Identical

303. I)

CH3

CH3H

H

Br

Br

II) CH3CH3

H HBr Br


304. I)

BrH

CH3

CH3

BrH

II)

CH3

CH3H

H

Br

Br


305.

BrH

CH3

CH3

Br H

Translating this Fischer projection formula into eclipsed sawhorse projection appears

(a) CH3 CH3

H HBr Br

(b) CH3 CH3

H HBr Br

(c) Both (a) and (b) d) None of these

306. I) 3 3CH CH II) 3 2 2 3CH CH CH CH III)

3 3

3 3

3 3

| |

| |

CH CH

CH C C CH

CH CH

Among these alkanes, the magnitude of energy required for rotation about indicated bonds is in the order as (a) I > II > III (b) III > II > I (c) III > I > II (d) II > III > I 307. From heat of combustion of isomers, one can predict the order of their (a) Stability (b) Optical activity (c) Reactivity (d) All of these 308. Which of the following relations is valid in case of isomers? (a) Stability of isomers their heat of combustion (b) Stability of isomers 1/their heat of combustion (c) Reactivity of isomers their heat of combustion (d) Reactivity of isomers 1/their heat of combustion

309. I) 3 2 2 3CH CH CH CH II)

3 3

3

|

CH CH CH

CH

Heat of combustion of I(n-butane) is found to be more than that of II (isobutene). It means that (a) Isobutane is more stable than n- butane (b) n-butane is more stable than isobutene (c) Energy content of n-butane is more than that of isobutene (d) Both (a) and (c)

310. I) 3 2 2 2 3CH CH CH CH CH II) 3 2 3

3

|

CH CH CH CH

CH

III) 3

3 3

3

|

|

CH

CH C CH

CH

Heat of combustion of these compounds is found in the order as I > II > III Then, which of the following statements is true (a) Stability order will be I > II > III and order of energy contents will be III > II > I (b) Stability order will be III > II > I and order of energy contents will be I > II > III (c) Stability order will be III > II > I and the order of energy contents will also be III > II > I (d) Stability order will be I > II > III and the order of energy contents will also be I > II > III

311. I) 3 2 2CH CH CH CH II)

CH3

CH3H

H

C = C

III)

CH3 CH3

H H

C = C

Heat of combustion of these isomers will be in the order as (a) I > II > III (b) III > II > I (c) III > I > II (d) I > III > II

312. Heat of combustion Heat of combustion Per 2CH (Kcal / mole) (Kcal/mole)

: - 499 .8 - 166.6

: - 656.0 - 164.0

: - 793.5 - 158.7

: - 944.4 - 157.4 Based on this experimentally derived table, stability order among these cyclanes is

(a) > > >

(b) > > >

(c) > > >

(d) > > >

313. Any deviation from excepted bond angle causes strain in the molecule. This strain is calleda angle strain. In case of

molecules containing 3sp -hybridized carbon atoms, angle straing can be calculated using which of the following

relations?

(a) Angle strain = 109 28'

2

o Actual angle

(b) Angle strain = 109 28'

2

o Actual angle

(c) Angle strain = 109 28' (2 )

3

o Actual angle (d) None of these

314. 600

In this molecule, angle strain is equal to

(a) 24 44 'o (b) 84 44 'o (c) 20o (d) 24o

315.

108o

In this molecule, angle strain is equal to

(a) 1 28'o (b) 44 (c) 2 36 'o (d) 42

316. 90o

In this molecule, angle strain is

(a) 3 44 'o (b) 4o (c) 9 44 'o (d) 5o

317.

120o

(Presuming Planar Ring) In this molecule, angle strain is equal to

(a) 5 44 'o (b) 5o (c) 2 44 'o (d) 5 16 'o 318. Calculated angle strain as in equestions 464 to 468

: 24 44 'o

: 9 44 'o

: 44 '

: 5 16o Based on these angle strains, stability order among these cyclanes should be

(a) > > >

(b) > > >

(c) > > >

(d) > > >

319. Experimentally found order of stability among these cyclanes, as given in question 463 is

> > >

On the other hand, based on calculated angle strains, derived order of stability among these cyclanes, as given

question 469 is

> > >

Both orders does not match completely with each other However, only the position of cyclohexane is dislocated, This

is because (a) Angle strain- theory is based on presumption that all rings are planar while cyclohexane ring is not planar (b) Angle strain theory is based on presumption that all rings is not planar (c) Cyclohexane ring exist mainly in chair from as

(Chair from) This conformer is free from all strains including angle strain because all angles are very close to

0 '109 28 (d) Both (a) and (c) 320. Which of the following is the least stable conformer of cyclohexane?

(a) (Chair) (b) (Boat) (c) (Twist boat) (d) (Half-chair) 321. Among chair, boat and twist boat conformers of cyclohexane, stability order is (a) Chair > boat > twist boat (b) Chair > twist boat > boat (c) Boat > chair > twist boat (d) Twist boat > boat > chair 322. The Newman projection formula of the chair from of cyclohexane is

(a)

H

H

H

H

H

HHH (b)

H

H

H

H HH

H

H (c) Both (a) and (b) (d) None of these 323. The Newman projection formula for the boat form of cyclohexane is

(a)

H

H

H

H

H

HHH (b)

H

H

H

H HH

H

H (c) Both (a) and (b) (d) None of these

324. How many isomers are possible from the molecular formula 4 8C H ? (a) 4 (b) 6 (c) 9 (d) 8

325. How many isomers are possible from the molecular formula 5 10C H ? (a) 9 (b) 12 (c) 13 (d) 15

326. How many isomers are possible from the molecular formula 4 7C H Br ? (a) 12 (b) 17 (c) 19 (d) 20

327. How many isomers are possible from 2C FCl Br I ? (a) 4 (b) 5 (c) 6 (d) 7

328.

H H

CHOCH3

H

+

(Cis) (Trans)

H CHO

CH3 H

This isomerization reaction is possible through (a) Resonance (b) Enolization (c) Deprotonation (d) The generation of carbanion

329.

H H

OH D H

HOH

D

H/H2O+

(Cis) (Trans) This isomerisation reaction is possible through (a) Resonance (b) Enolization (c) Generation of carbanion (d) Generation of carbocation

junior chem 29-07-15 isomerisam holiday assignment

Documents

ch ch ch ch chbr br

ch c ch c chbr d

ch ch ch chbr br br

ch c ch c chch br ch

ch ch ch chci br d

ch ch chi br br d

ch ch ch chbr c oh d

br b bro c br d