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Isomerism · Question 14

AIPMT 2015MCQEasy📈 Topic in 0% papers+4−1
1

The possible stereo-structures of CH3CHOHCOOH, which are optically active, are called

  1. atropisomers
  2. enantiomers
  3. mesomers
  4. diastereomers

Answer

(2) enantiomers

Solution

CH3- *CH(OH)-COOH (lactic acid) has one chiral carbon (four different groups: H, CH3, OH, COOH).

⇒ It exists as two optically active forms, (+) and (–), which are non-superimposable mirror images of each other.

As per NCERT, stereoisomers related as non-superimposable mirror images are called enantiomers.

Answer: (2)

AIPMT 2015

Keep practising — Isomerism

2

In an SN1 reaction on chiral centers, there is

  1. inversion more than retention leading to partial racemisation
  2. 100% retention
  3. 100% inversion
  4. 100% racemisation
AIPMT 2015
3

The number of structural isomers possible from the molecular formula C3H9N is

  1. 5
  2. 2
  3. 3
  4. 4
AIPMT 2015
4

Given : [figure] Which of the given compounds can exhibit tautomerism?

  1. II and III
  2. I, II and III
  3. I and II
  4. I and III
AIPMT 2015 (Cancelled)
5

Which of the following compounds will undergo racemisation when solution of KOH hydrolyses? [figure]

  1. (i) and (ii)
  2. (ii) and (iv)
  3. (iv)
  4. (i) and (iv)
AIPMT 2014
6

The order of stability of the following tautomeric compounds is [figure]

  1. II > I > III
  2. II > III > I
  3. I > II > III
  4. III > II > I
NEET 2013
7

Given: [figure] I and II are

  1. identical
  2. a pair of conformers
  3. a pair of geometrical isomers
  4. a pair of optical isomers
NEET 2013 (Karnataka)
8

Number of isomeric alcohols of molecular formula C6H14O which give positive iodoform test is

  1. three
  2. four
  3. five
  4. two
NEET 2013 (Karnataka)
9

Which of the following acids does not exhibit optical isomerism?

  1. Maleic acid
  2. -amino acids
  3. Lactic acid
  4. Tartaric acid
AIPMT 2012 (Prelims)
10

The IUPAC name of the following compound is [figure]

  1. trans-2-chloro-3-iodo-2-pentene
  2. cis-3-iodo-4-chloro-3-pentene
  3. trans-3-iodo-4-chloro-3-pentene
  4. cis-2-chloro-3-iodo-2-pentene
AIPMT 2011 (Mains)
11

Which of the following conformers for ethylene glycol is most stable?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2010 (Mains)

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