The molarity of $HNO_{3}$ in a sample which has density $1.4 \; g/mL$ and mass percentage of $63\%$ is . . . . . . $M$.
(Molecular Weight of $HNO_{3} = 63$)

The molarity of $1 \ L$ orthophosphoric acid $(H_3PO_4)$ having $70 \%$ purity by weight (specific gravity $1.54 \ g \ cm^{-3}$) is $ . . . . . . $ $M$.
(Molar mass of $H_3PO_4 = 98 \ g \ mol^{-1}$)

If $1\frac{1}{2}$ moles of oxygen combine with $Al$ to form $Al_2O_3$,the weight of $Al$ used in the reaction is ............. $g$ $(Al=27)$.

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

$A$ spherical ball of radius $7 \ cm$ contains $56 \ w\%$ iron. Find out the number of moles of iron present approximately in the ball (in $.1$)? $(d = 1.4 \ g \ cm^{-3}; \text{atomic mass} = 56 \ g \ mol^{-1})$

Dissolving $120 \ g$ of a compound (mol. wt. $60$) in $1000 \ g$ of water gave a solution of density $1.12 \ g/mL$. The molarity of the solution is ............ $M$.