$A$ hydrocarbon contains $75\%$ carbon by mass. What is its empirical formula?

An organic compound on analysis gave $C = 48 \,g$, $H = 8 \,g$ and $N = 56 \,g$. The volume of $1.0 \,g$ of the compound was found to be $200 \,mL$ at $NTP$. What is the molecular formula of the compound?

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:

The molecular mass of caffeine is $194 \, a.m.u.$. It contains $28.9 \%$ of nitrogen by mass. The number of nitrogen atoms in one molecule of caffeine is ...............

On analysis,a certain compound was found to contain iodine and oxygen in the ratio of $254 \ g$ of iodine and $80 \ g$ of oxygen. The atomic mass of iodine is $127$ and that of oxygen is $16$. Which of the following is the formula of the compound?

An organic compound contains $78\%$ (by $wt.$) carbon and the remaining percentage of hydrogen. The correct option for the empirical formula of this compound is: [Atomic $wt.$ of $C$ is $12$,$H$ is $1$]