Give possible explanation for the following : (ii) There are two - `NH_2` groups is semicarbazide . However, only one is involved in formation of semi carbonzone.

(a) Give a plausible expianation for each one of the following : - (i) There are two - NH_(2) groupsin semicarbazide. However, only one such group is involvedin the formation of semicarbazones. (ii) Cyclohexanone forms cyanohydrin in good yield but 2,4,6 -trimethylcyclohexanone does not. (b) An organic compound with molecular formula C_(9)H_(10)O forms, 2,4 - DNP derivative, reduces Tollens' reagent and undergoes Cannizzaro reaction. On vigorous oxidation it gives 1,2-benzene-di-carboxylic acid. Identify the compound.

Giving plausible explanation for each of the following: i. Cyclohexanone forms cyanohydrin good yield but 2,2,6-trimethylcyclohexanone does not. ii. There are two (-NH_(2)) groups in semicarbazide. However, only one is involved in the formation of semicarbazones. iii. During the preparation of esters from a carboxylic acid and an alcohol in the ester should be removed as soon as it is formed.

Give the decresing order of boiling points for the following : I. Et_2NH II

Give reasons for the following in one or two sentences only : ''BeCl_(2) can be easily hydrolysed.