Give reason for the following:(i) Aldehydes are more reactive than ketones towards nucleophilic reactions.(ii) pKa value of acetic acid is higher than pKa value of chloroacetic acid.

(1)Aldehydes are usually more reactive toward nucleophilic substitutions than ketones because of both steric and electronic effects. In aldehydes, the relatively small hydrogen atom is attached to one side of the carbonyl group, while a larger R group is affixed to the other side. In ketones, however, R groups are attached to both sides of the carbonyl group. Thus, steric hindrance is less in aldehydes than in ketones.
(2)pkaofacetic acid is 4.23 and chloroacetic acid is 2.3.​
pKavalue depends upon the strength of acid. The stronger acid will have lesser pKavalue and weaker acid will have higher pKa value.The value indicates that chloroacetic acid is stronger acid than acetic acid.
This can be explained on the basis of inductive effect of Cl.Cl being highly electronegative will pull the electrons towards itself This will polarize the C-Cl bond and in turn also polarize the C-O and O-H bonds.Due to this there would be easy removal of H+ ion. Moreover anion formed by removal of H+will also stabilized by electron pulling nature of Cl.