An organic compound with $C = 40\%$ and $H = 6.7\%$ will have the empirical formula

What is the percentage of nitrogen in urea (in $\%$)?

The ratio of the mass percentages of $C$ and $H$ and $C$ and $O$ of a saturated acyclic organic compound $X$ are $4 : 1$ and $3 : 4$ respectively. Then,the moles of oxygen gas required for complete combustion of two moles of organic compound $X$ is

In a hydrocarbon,the mass ratio of hydrogen and carbon is $1 : 3$. The empirical formula of the hydrocarbon is

Urea is a better fertilizer than ammonium sulphate because

Analysis of an organic compound shows $C = 40\%$,$H = 13.33\%$,and $N = 46.67\%$. Its empirical formula is ....