If equal masses of methane $(CH_4)$ and hydrogen $(H_2)$ are mixed in an empty container at $25\,^oC$,what is the fraction of the total pressure exerted by hydrogen?

$A$ $250 \, mL$ solution of $Na_2CO_3$ contains $2.65 \, g$ of $Na_2CO_3$. If $10 \, mL$ of this solution is taken and diluted with distilled water up to $0.1 \, L$,what will be the molarity of the resulting solution (in $, M$)?

The molecular weight of a gas is $45$. Its density at $STP$ is

When $1 \ dm^{3}$ of $CO_{2}$ gas is passed over hot coke, the volume of the gaseous mixture after the complete reaction at $STP$ becomes $1.4 \ dm^{3}$. The composition of the gaseous mixture at $STP$ is:

If salicylic acid $(138 \text{ u})$ reacts with acetic anhydride $(102 \text{ u})$ to form aspirin $(180 \text{ u})$ and acetic acid $(60 \text{ u})$,calculate the percentage atom economy. (in $\%$)

$5 \, mL$ of $N$ $HCl$,$20 \, mL$ of $N/2$ $H_2SO_4$,and $30 \, mL$ of $N/3$ $HNO_3$ are mixed together and the volume is made up to $1 \, L$. The normality of the resulting solution is: