In the reaction $2P_2O_5 + 2HNO_3 \to P_4O_{10} + X$,what is the product $X$?

What volume of hydrogen gas at $STP$ would be liberated by the action of $50 \text{ mL}$ of $H_2SO_4$ of $50\%$ purity (density = $1.3 \text{ g mL}^{-1}$) on $20 \text{ g}$ of zinc (in $L$)? Given: Molar mass of $H, O, S, Zn$ are $1, 16, 32, 65 \text{ g mol}^{-1}$ respectively.

$5 \ mL$ of $0.1 \ M \ Pb(NO_{3})_{2}$ is mixed with $10 \ mL$ of $0.02 \ M \ KI$. The amount of $PbI_{2}$ precipitated will be about

The action of steam on heated iron is represented as:

Calculate the weight of $CaO$ formed in quintals when $10 \ g$ of $CaCO_3$ is heated with $4.4 \ g$ of $CO_2$.

The yield of $acetanilide$ in the reaction ($100\%$ conversion) of $2$ moles of $aniline$ with $1$ mole of $acetic$ $anhydride$ is (in $g$)