Question

Which of the following molecules has all the effects: inductive, mesomeric and Baker Nathan effect?
A. ${{C}_{2}}{{H}_{5}}Cl$
B. $C{{H}_{3}}CH=C{{H}_{2}}$
C. $C{{H}_{2}}=CHCH=C{{H}_{2}}$
D. $C{{H}_{3}}CH=CHC=O-C{{H}_{3}}$

Answer 1

Hint To get the appropriate answer of this question, first of all try to explain what inductive effect, mesomeric effect and Baker Nathan effect (also called as electromeric effect). Then, try to draw a conclusion checking into each option consisting what types of effects they have.

Complete step by step solution:
First of all, let us know some of the terms before going to know the answer of this question.
So, coming to the term inductive effect:
- Inductive effect: Inductive effect occurs in a molecule because of the unequal sharing of the bonding electrons within the molecule. The inductive effect is seen by sigma bonds while the electromeric effect is seen by pi-bonds only.
- Mesomeric effect: The polarity developed between atoms of a conjugated system by the electron transfer or pi-bond electron transfer is known as the mesomeric effect. This occurs when pi electrons move away from or towards a substituent group in a conjugated orbital system.
- Baker effect: The Baker effect or ‘electromeric effect’ or ‘hyperconjugation’, is a temporary effect mainly experienced in the presence of an attacking reagent in the vicinity of an organic compound having multiple bonds (a double or triple bond). In this effect, the complete transfer of a shared pair of pi electrons to one of the atoms joined by multiple bonds on the demand of an attacking reagent takes place. So, here in the question let us consider all molecules one by one. For the first option, there is no Baker effect or mesomeric effect while in the second and third option, the molecules are all alkyl groups. Hence, there will be no inductive effect. And in the fourth option, the respective molecule shows all the effects where, the $-C=O$ group will show the inductive effect as oxygen is electronegative, the $-CH=CH-C=O$ group will show mesomeric effect due to the presence of conjugated double bonds and Baker effect is also seen, as it has free pi electrons.

Hence, the correct option is D.

Note: Remember, the inductive effect is seen where there is presence of electronegative atom while mesomeric effect is seen by a molecule due to presence of conjugated double or triple bonds and Baker effect is due to the presence of free pi orbitals.