Compound `(A) ( C_(6)H_(8))overset([o])(rarr)` Malonic acid only. Identify compound `(A)`.

Explanation

First, calculate the degree of unsaturation.
`D.U.=((2n_(C)+2)-n_(H))/(2)=((2xx6+2)-8)/(2)=3^(@)`
Structure of malonic acid is
It is a `3 C-` atom dibasic acid, but compound `(A)` has six `C` atoms. So, `2 mol` are joined with each other.