$A$ mixture of gases contains $H_2$ and $O_2$ gases in the ratio of $1 : 4$ $(w/w)$. What is the molar ratio of the two gases in the mixture?

What volume (in $mL$) of gaseous $NH_3$ at $N.T.P.$ is required to be passed into $30 \, mL$ of $1 \, N \, H_2SO_4$ solution to reduce the acid strength of this solution to $0.2 \, N$?

$A$ gaseous mixture contains $CH_4$ and $C_2H_6$ in equimolecular proportion. The weight of $2.24 \ L$ of this mixture at $S.T.P.$ is :- .............. $g$

$A$ solution contains $1.2046 \times 10^{24}$ hydrochloric acid molecules in one $dm^3$ of the solution. The strength of the solution is .......... $N$.

$A$ hydrocarbon containing $C$ and $H$ has $92.3 \% C$. When $39 \ g$ of hydrocarbon was completely burnt in $O_2$,$x$ moles of water and $y$ moles of $CO_2$ were formed. $x$ moles of water is sufficient to liberate $0.75$ moles of $H_2$ with $Na$ metal. What is the weight (in $g$) of oxygen consumed? $(C=12 \ u; H=1 \ u)$

$1.86 \ g$ of aniline completely reacts to form acetanilide. $10 \ \%$ of the product is lost during purification. Amount of acetanilide obtained after purification (in $g$) is ...... $\times 10^{-2}$.