Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is…

Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is
Given : Molar mass of Mg is $24 \mathrm{~g} \mathrm{~mol}^{-1}$.
  1. 235.7 g
  2. 0.24 mg
  3. 236 mg
  4. 2.444 g

Solution

$\mathrm{Mg}+2 \mathrm{HCl} \rightarrow \mathrm{MgCl}_2+\mathrm{H}_2$
Volume $\mathrm{H}_2$ evolved $=220 \mathrm{ml}$
Mole of $\mathrm{H}_2=\frac{220 \times 10^{-3}}{22.4}=$ mole of Mg used
$\begin{aligned}
\therefore \text { Mass of Mg used } & =\frac{220 \times 10^{-3}}{22.4} \times 24 \\
& =235.7 \times 10^{-3} \mathrm{gm} \\
& =235.7 \mathrm{mg}
\end{aligned}$

Asked in: JEE Main 2025 (03 Apr Shift 2)

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