What is produced when $1 \ mol$ of calcium phosphide reacts with excess water?
$(Hint: Ca_3P_2 + H_2O (excess) \rightarrow Ca(OH)_2 + 2PH_3)$

Mass of $NaOH$ required for formation of $100 \ mL$ of its decimolar solution is .............. $g$.

$A$ metal chloride contains $71\%$ chlorine by mass and has a vapor density of $50$. What is the atomic mass of the metal?

At constant temperature and pressure,the change in volume when $80\%\, 100\, mL$ of phosgene $(COCl_2)$ decomposes into $CO$ and $Cl_2$ is an increase of ............... $mL$.

Fortification of food with iron is done using $FeSO_4 \cdot 7 H_2 O$. The mass in grams of the $FeSO_4 \cdot 7 H_2 O$ required to achieve $12 \ ppm$ of iron in $150 \ kg$ of wheat is $..........$ (Nearest integer).
[Given: Molar mass of $Fe, S$ and $O$ respectively are $56, 32$ and $16 \ g \ mol^{-1}$]

What volume of dioxygen is required for complete combustion of $2 \, \text{volumes}$ of acetylene gas at $NTP$?