Partially dried soil contains $50 \%$ silica and $7 \%$ water. If the original soil contained $12 \%$ water,then the percentage of silica in the original soil is .............. $\%$.

$0.05 \ cm$ thick coating of silver is deposited on a plate of $0.05 \ m^2$ area. The number of silver atoms deposited on the plate is . . . . . . $\times 10^{23}$. (Atomic mass of $Ag = 108$,density $d = 7.9 \ g \ cm^{-3}$)

Density of a $2.05 \ M$ solution of $H_2SO_4$ in water is $1.08 \ g/mL$. Find its Normality and molality.

Which of the following formulas is correctly represented according to Stock notation?

$10 \, mL$ of concentrated $H_2SO_4$ $(18 \, M)$ is diluted to $1 \, L$. The approximate strength of the dilute acid is.....$N$

Chlorophyll extracted from the crushed green leaves was dissolved in water to make $2 \, L$ solution of $Mg$ of concentration $48 \, ppm$. The number of atoms of $Mg$ in this solution is $x \times 10^{20}$ atoms. The value of $x$ is (Nearest Integer) (Given : Atomic mass of $Mg$ is $24 \, g \, mol^{-1}$,$N_{A} = 6.02 \times 10^{23} \, mol^{-1}$)