$0.765 \ g$ of an acid gives $0.535 \ g$ of $CO_2$ and $0.13 \ g$ of $H_2O$. The ratio of the percentage of $C$ and $H$ is:

Carbon percentage is maximum in

An organic compound has $42.1 \%$ carbon,$6.4 \%$ hydrogen and the remainder is oxygen. If its molecular weight is $342$,then its molecular formula is:

$C_4H_6O_2$ does not represent :

$A$ compound $X$ contains $32 \%$ of $A$,$20 \%$ of $B$,and the remaining percentage of $C$. Then,the empirical formula of $X$ is:
(Given atomic masses of $A = 64$,$B = 40$,$C = 32 \ u$)

$A$ $64 \, g$ organic compound contains $24 \, g$ of carbon,$8 \, g$ of hydrogen,and the rest is oxygen. The empirical formula of this compound is .....