What volume (in $mL$) of $0.1 \ M \ KOH$ solution is required for the complete neutralization of $20 \ mL$ of $0.1 \ M$ phosphorous acid $(H_3PO_3)$?

What volume of $CO_{2(g)}$ at $STP$ is obtained by complete combustion of $6 \ g$ carbon (in $dm^3$)?

$20 \ mL$ of $CO_2$ gas are passed over excess of red hot coke. The volume of $CO$ evolved is ............. $mL$.
$CO_{2(g)} + C_{(s)} \to 2CO_{(g)}$

The mass of a mixture containing $NaCl$ and $NaBr$ is $4.0 \ g$. If $Na$ is $30 \%$ of the total mixture,the composition of $NaCl$ in the mixture is (in $\%$)

What is the value of $w$ (mass of solute in grams) required to prepare a definite volume of a standard solution of known normality $(N)$?
[$N = \text{normality}$,$E = \text{equivalent weight}$,$V = \text{volume of solution in } mL$]

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 $16 \ g \ mol^{-1}$]