The weight of $H_2C_2O_4 \cdot 2H_2O$ required to prepare $500 \ mL$ of $0.2 \ N$ solution is .......... $g$.

The concentrated sulphuric acid that is peddled commercially is $95\%\, H_2SO_4$ by weight. If the density of this commercial acid is $1.834\, g\, cm^{-3},$ the molarity of this solution is ........... $M$.

$10 \text{ g}$ of a mixture of $BaO$ and $CaO$ requires $100 \text{ cm}^3$ of $2.5 \text{ M } HCl$ to react completely. The percentage of calcium oxide in the mixture is approximately (Given: molar mass of $BaO = 153 \text{ g/mol}$,$CaO = 56 \text{ g/mol}$).

How many $mL$ of $0.1\, M\, HCl$ are required to react completely with $1\, g$ mixture of $Na_2CO_3$ and $NaHCO_3$ containing equimolar amounts of both?

How many moles of $H_2O$ are liberated when one mole of hydrated $MgCl_2$ is heated?

What is the weight of oxygen that is required for the complete combustion of $2.8 \ kg$ of ethylene? (in $kg$)