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)
D. 7.1
The balanced redox equation is: MnO _2 + 4 HCl MnCl _2 + Cl _2 + 2 H _2 O . Molar mass of MnO₂ = 55 + 32 = 87 g/mol. Moles of MnO₂ = 8.7 87 = 0.1 mol. From stoichiometry, 1 mol MnO₂ produces 1 mol Cl₂, so 0.1 mol produces 0.1 mol Cl₂. Mass of Cl₂ = 0.1 71 = 7.1 g.
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