JEE Main 2020 — Some Basic Concepts Of Chemistry Question with Solution
From: JEE Main 2020 (Online) 4th September Morning Slot
Question
A 20.0 mL solution containing 0.2 g impure
H2O2 reacts completely with 0.316 g of KMnO4
in acid solution. The purity of H2O2 (in %) is
_____________
(mol. wt. of H2O2 = 34; mol. wt. of KMnO4 = 158)
(mol. wt. of H2O2 = 34; mol. wt. of KMnO4 = 158)
Enter your answer
Show full solutionCorrect answer: 85
Correct answer
85
Step-by-step explanation
5H2O2 + 2MnO4- + 6H+ 2Mn2+ + 5O2 + 8H2O
Moles of KMnO4 = = 2 10-3
Equivalents of H2O2 = Equivalent of KMnO4
= 2 × 10–3 × 5 = 0.01
Moles of H2O2 = = 0.005
Mass of pure H2O2 = 0.005 × 34 = 0.170 gm
Percentage purity = 100 = 85 %
Moles of KMnO4 = = 2 10-3
Equivalents of H2O2 = Equivalent of KMnO4
= 2 × 10–3 × 5 = 0.01
Moles of H2O2 = = 0.005
Mass of pure H2O2 = 0.005 × 34 = 0.170 gm
Percentage purity = 100 = 85 %
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