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

$A$ substance contains $38.8\% \, C$,$16\% \, H$,and $45.2\% \, N$. What is the empirical formula of the substance?

$A$ compound contains $4.07\%$ hydrogen,$24.27\%$ carbon,and $71.65\%$ chlorine. Its molar mass is $98.96\ g/mol$. What are its empirical and molecular formulas?

The empirical formula of a compound is $CH_2O$ and its molecular mass is $180$. The molecular formula of this compound is .....

What is the percentage by mass of oxygen in $NaOH$? (Atomic mass of $Na=23 \ u, O=16 \ u, H=1 \ u$)

$A$ welding fuel gas contains carbon and hydrogen only. Burning a small sample of it in oxygen gives $3.38 \ g$ of carbon dioxide,$0.690 \ g$ of water and no other products. $A$ volume of $10.0 \ L$ of this welding gas (measured at $STP$) is found to weigh $11.6 \ g$. Calculate: $(i)$ Empirical formula,$(ii)$ Molar mass of the gas,$(iii)$ Molecular formula.