Number of hydrogen atoms per molecule of a hydrocarbon $A$ having $85.8 \%$ carbon is $...............$. (Given : Molar mass of $A = 84 \ g \ mol^{-1}$ )

The empirical formula of an acid is $CH_2O_2$. The molecular formula of this acid will be .....

$A$ metal $M$ sulfate contains $9.87 \% \, M$. If it is isomorphous with $ZnSO_4 \cdot 7H_2O$,what is the atomic mass of $M$ (in $.3$)?

Complete combustion of $1.80 \, g$ of an oxygen-containing compound $(C_xH_yO_z)$ gave $2.64 \, g$ of $CO_2$ and $1.08 \, g$ of $H_2O$. The percentage of oxygen in the organic compound is

$A$ compound contains $10^{-2} \%$ of phosphorus. If the atomic mass of phosphorus is $31$,the molecular mass of the compound having one phosphorus atom per molecule is :-

$A$ hydrocarbon contains $85.7 \% C$. If $42 \, mg$ of the compound contains $3.01 \times 10^{20}$ molecules,the molecular formula of the compound will be