$0.5 \ g$ of hydrocarbon gave $0.9 \ g$ of water on combustion. The percentage of carbon in the hydrocarbon is:

An organic compound contains $C = 74.0\%$,$H = 8.65\%$ and $N = 17.3\%$. Its empirical formula is:

$A$ gaseous compound of nitrogen and hydrogen contains $12.5\%$ (by mass) of hydrogen. The density of the compound relative to hydrogen is $16$. The molecular formula of the compound is

$0.44 \ g$ of a colourless oxide of nitrogen occupies $224 \ mL$ at $\text{STP}.$ The compound is $-$

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

An organic compound on analysis gave the following results: $C = 54.5\%$,$O = 36.4\%$,$H = 9.1\%$. The empirical formula of the compound is: