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Question: What are \[E\] and \[Z\;\] isomers of cinnamic acid? A) ![](https://www.vedantu.com/question-sets/...

What are EE and Z  Z\; isomers of cinnamic acid?
A) and
B) and
C) and
D) None of the above

Explanation

Solution

We have to remember that the cinnamic acid is 3phenylpropanoicacid3 - phenylpropanoic acid
We can draw the structure of cinnamic acid:

Complete step by step answer:
Before solving this question we will look at the structure of cinnamic acid and more about isomers.
Isomers are molecules with the same molecular formula and different arrangement.
Isomers can be of two types i) structural isomers ii) Stereoisomers
E/ZE/Z isomers come under the category of Stereoisomers.
EE isomer: This notation is used when the groups with higher priority are on the opposite side.
ZZisomer: This notation is used when the groups with higher priority are on the same side.
In case of Cinnamic acid,
It is 3phenylpropanoicacid3 - phenylpropanoic acid
Structure of 3phenylpropanoicacid3 - phenylpropanoic acid is

ZCinnamic acidZ - Cinnamic{\text{ }}acid \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ECinnamic acidE - Cinnamic{\text{ }}acid
E/ZE/Z isomers are as follows:
Phenyl ring and Carboxylic acid group are the one with higher priority than H atoms.
Out of COOHCOOH and Phenyl ring, COOHCOOH will have the priority as 1 followed by Phenyl ring C6H5{C_6}{H_5}, Therefore when both these groups are on the same side, this will represent ZCinnamicAcidZ - Cinnamic Acid i.e. Z  Z\; isomer.
And when both these groups are on the opposite side, this will represent ECinnamicAcidE - Cinnamic Acid i.e. EE isomer.
Option A) this is an incorrect option since cinnamic acid is 3phenylpropanoicacid3 - phenylpropanoic acidbut the structure given in this option is not 3phenylpropanoicacid3 - phenylpropanoic acidthus we can neglect this option.
Option B) This is a correct option as 3phenylpropanoicacid3 - phenylpropanoic acid is the molecular formula for cinnamic acid.
Option C) this is an incorrect option.
Option D) this is an incorrect option as we got a correct option i.e. B

Hence, the correct option is ‘Option D’

Note: For solving this type of questions one must look at the structural as well as molecular formula for the compound given, this makes it easy to solve the question.