Aqueous HCl reacts with $\mathrm{MnO}_{2}(\mathrm{~s})$ to form $\mathrm{MnCl}_{2}(\mathrm{aq})$, $\mathrm{Cl}_{2}(\mathrm{~g})$ and $\mathrm{H}_{2} \mathrm{O}(l)$. What is the weight (in g) of $\mathrm{Cl}_{2}$ liberated when 8.7 g of $\mathrm{MnO}_{2}(\mathrm{~s})$ is reacted with excess aqueous HCl solution? (Given Molar mass in $\mathrm{g} \mathrm{mol}^{-1}$ Mn=55, Cl=35.5, O=16, H=1)

JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Redox Reactions and Electrochemistry

Aqueous HCl reacts with

MnO_{2} (s)

to form

MnCl_{2} (aq)

Cl_{2} (g)

and

H_{2} O (l)

. What is the weight (in g) of

Cl_{2}

liberated when 8.7 g of

MnO_{2} (s)

is reacted with excess aqueous HCl solution? (Given Molar mass in

g mol^{- 1}

Mn=55, Cl=35.5, O=16, H=1)

Answer: (A)

The balanced redox change is

MnO_{2} + 4 HCl \to MnCl_{2} + Cl_{2} + 2 H_{2} O

, so one mole of manganese dioxide liberates one mole of chlorine. The molar mass of

MnO_{2}

55 + 32 = 87 g mo l^{- 1}

, and

8.7 g

0.1 mol

, which yields

0.1 mol

Cl_{2}

. At

71 g mo l^{- 1}

this weighs

0.1 \times 71 = 7.1 g

. The mass of chlorine liberated is 7.1 g.

JEE Main · 2026 · 21 Jan 2026 · Shift 2 · Single correct option