An organic compound having molecular mass 60 is found to contain C = 20%, H = 6.67% and N = 46.67% while rest is oxygen. On heating it gives NH₃ along with a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is

In both DNA and RNA, heterocyclic base and phosphate ester linkages are at-

Reaction of cyclohexanone with dimethylamine in the presence of catalytic amount of an acid forms a compound if water during the reaction is continuously removed. The compound formed is generally known as

The decreasing order of nucleophilicity among the nucleophiles