$CaCO _{3( s )}+2 HCl _{( aq )} \rightarrow CaCl _{2( aq )}+ CO _{2( g )}+2 H _{2} O _{( l )}$
[બે દશાંશ બિંદુ સુધી ગણતરી કરો]
no. of moles of $CaCO _{3}$ (pure) $=\frac{1}{2} \times$ mole of $HCl$
$\quad \text { [Mole }=\text { molarity } \times \text { volume(in Itr. }) \text { ] }$
$=\frac{1}{2} \times 0.5 \times \frac{50}{1000}=0.0125$
weight of $CaCO _{3}$ (pure) $=$ mole $\times$ mol. wt
$=0.0125 \times 100=1.25 \,g$
$\%$ purity $=\frac{\text { wt. of pure substance }}{\text { wt. of impure sample }} \times 100$
$95=\frac{1.25}{\text { wt. of impure sample }} \times 100$
wt. of impure sample $=\frac{1.25 \times 100}{95}=1.32 \,g$
(આપેલ : મોલર દળ $\mathrm{g} \mathrm{mol}^{-1}$ છે. ઈથાઈલ આલ્કોહોલ : $46$, પાણી : $18$)
કારણ : $H_3PO_3$ નો તુલ્યભાર = $\frac{Molecular\, weight\, of\, H_3PO_3}{3}$