Question

By starting with 0.5 moles of sodium peroxide how many moles of dioxygen gas can be obtained by dropping excess of acidified potassium permanganate solution on it?

• A. 0.125 mole
• B. 1 mole
• C. 0.25 mole
• D. 0.5 mole

Answer 1

Answer: (D)

$2KMnO_{4}+5Na_{2}O_{2}+8H_{2}SO_{4} \rightarrow K_{2}SO_{4}+2MnSO_{4}+5Na_{2}SO_{4}+8H_{2}O+5O_{2}$
$\text{5} \, \text{mole} \, \text{Na}_{\text{2}} \text{O}_{\text{2}} \text{O}_{\text{2}} \, \text{=} \, \text{5}$ gives $\text{O}_{\text{2}} \, \text{=} \, \text{5} \, \text{mole}$
So $\text{0} \text{.5} \, \text{mol} \, \text{Na}_{\text{2}} \text{O}_{\text{2}}$ give $\text{O}_{\text{2}} \, \text{=} \, \text{0} \text{.5} \, \text{mol}$