Question -
Answer -
(i) CH3CO2H orCH2FCO2H
(ii)CH2FCO2H orCH2ClCO2H
(iii) CH2FCH2CH2CO2H or CH3CHFCH2CO2H
(iv)
Answer
(i)
The +I effect of −CH3 groupincreases the electron density on the O−H bond. Therefore, release of protonbecomes difficult. On the other hand, the −I effect of F decreases the electrondensity on the O−H bond. Therefore, proton can be released easily. Hence, CH2FCO2H isa stronger acid than CH3CO2H.
(ii)
F has stronger −I effect than Cl. Therefore,CH2FCO2H can release proton more easily than CH2ClCO2H.Hence, CH2FCO2H is stronger acid than CH2ClCO2H.
(iii)
Inductive effect decreases with increase indistance. Hence, the +I effect of F in CH3CHFCH2CO2H ismore than it is in CH2FCH2CH2CO2H. Hence, CH3CHFCH2CO2H isstronger acid than CH2FCH2CH2CO2H.
(iv)
Due to the −I effect of F, it is easier torelease proton in the case of compound (A). However, in the case of compound(B), release of proton is difficult due to the +I effect of −CH3 group.Hence, (A) is a stronger acid than (B).