$A$ gaseous hydrocarbon gives upon combustion $0.72 \ g$ of water and $3.08 \ g$ of $CO_{2}$. The empirical formula of the hydrocarbon is:

$25 \ g$ of an unknown hydrocarbon upon burning produces $88 \ g$ of $CO_2$ and $9 \ g$ of $H_2O$. This unknown hydrocarbon contains:

An organic compound contains $49.3\%$ carbon,$6.84\%$ hydrogen,and the rest is oxygen. Its vapor density is $73$. What is its molecular formula?

The empirical formula of a compound is $CH_2O$ and its molecular mass is $90$. The molecular formula of the compound is:

The percentage of $P_2O_5$ in diammonium hydrogen phosphate $(NH_4)_2HPO_4$ is

An organic compound having molecular mass $60$ is found to contain $C = 20\%$,$H = 6.67\%$,and $N = 46.67\%$,while the rest is oxygen. On heating,it gives $NH_3$ along with a solid residue. The solid residue gives a violet color with alkaline copper sulphate solution. The compound is: