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

Carbon percentage is maximum in

$A$ 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 :-

The empirical formula of an acid is $CH_2O_2$. The probable molecular formula of the acid may be:

An oxide of sulfur contains $50\%$ sulfur. What is its empirical formula?

Haemoglobin contains $0.33 \%$ of iron by mass. The molecular mass of haemoglobin is $67200$. The number of iron atoms present in one molecule of haemoglobin is: (Atomic mass of $Fe = 56$)