The normality of orthophosphoric acid having purity of $70\%$ by weight and specific gravity $1.54$ would be ............. $N$.

Find the volume of $56 \ g$ of dinitrogen $(N_2)$ at $STP$. (in $L$)

Calcium carbonate reacts with aqueous $HCl$ to give $CaCl_{2}$ and $CO_{2}$ according to the reaction,
$CaCO_{3(s)} + 2HCl_{(aq)} \rightarrow CaCl_{2(aq)} + CO_{2(g)} + H_{2}O_{(l)}$
What mass of $CaCO_{3}$ is required to react completely with $25 \ mL$ of $0.75 \ M$ $HCl$ (in $g$)?

In the combustion of $2.0 \ g$ of methane,$25 \ kcal$ of heat is liberated. The heat of combustion of methane would be ..... $kcal$.

$A$ gas mixture contains $25 \%$ He and $75 \% CH_4$ by volume at a given temperature and pressure. The percentage by mass of methane in the mixture is approximately . . . . . . (in $\%$)

In an aqueous solution of $A_2B_3$,it undergoes complete ionization according to the reaction $A_2B_3 \rightleftharpoons 2A^{+3} + 3B^{-2}$. The concentration of $A^{+3}$ is equal to......