29Ans 21 ..due to peracid epoxy rings are formed..but i think in the presence of H+ the epoxy ring due to it's less stability will break to form 2,3 butane diol..maybe the answer given is wrong
Ans 22 ..well i think it forms Chloronium ion
Ans24...Carbene intermediate is formed...since both the CH3 groups are on the same side in reactant..so they shud be on the same side in product also ..so it is C
Ans 25..OsO4 form syn - diol so the compound will have a plane of symmetry..hence it is meso..