One litre of hard water contains $12.00 \ mg$ of $Mg^{2+}$. The milli-equivalents of washing soda $(Na_2CO_3)$ required to remove its hardness is:

How many $mL$ of $1 \, M$ $H_2SO_4$ is required to neutralize $10 \, mL$ of $1 \, M$ $NaOH$ solution?

$A$ gaseous mixture contains $CH_4$ and $C_2H_6$ in equimolecular proportion. The weight of $2.24 \ L$ of this mixture at $S.T.P.$ is :- .............. $g$

$100 \, mL$ of a given $H_2O_2$ sample in water (density $1.08 \, g/mL$) required $5 \, mL$ of $M/25 \, KMnO_4$ in acidic medium for its oxidation. Select the correct statement regarding $H_2O_2$ in the sample:

For the combustion reaction of $1 \ mol$ of benzene,if all reactants and products are in the gaseous state,then $\Delta n_{(g)}$ is equal to ......

$A$ person consumes $640 \, g$ of $O_2$ daily. If all the $O_2$ is used for the conversion of sugar into $CO_2$ and $H_2O$,how much sucrose $(C_{12}H_{22}O_{11})$ is consumed in the body per day and how much heat in $kJ$ is produced (in $.33$)? Given: $\Delta H_{combustion} \text{ of sucrose} = -5645 \, kJ \, mol^{-1}$.