(d)
Amount of pure lime stone $\left( CaCO_{3} \right)is\ 10\ g\ of\ 90\%\ sample$
$= \frac{90}{100} \times 10 = 9\ g$
$CaCO_{3}\overset{\ \ \ \ \ \ \ \ \ \ \ \ \mathrm{\Delta}\ \ \ \ \ \ \ \ \ \ \ \ }{\rightarrow}CaO + CO_{2}$
100 g 22.4 L
100 g of lime stone gives 22.4 L of $CO_{2}$ at STP
$\therefore$ 9 g of lime stone will give
$= \frac{22.4}{100} \times 9 = 2.016\ L\ CO_{2}$