A saturated aliphatic compound $A$ has the formula $C_4H_8O$. 1) A gives a yellow precipitate with DNPH. What can we say? 2) A gives a positive reaction with Fehling's solution. What can we say more? 3) Oxidation of A by acidic potassium dichromate solution gives product $B$ with a branched chain. Identify $A$ !
