A polyvalent metal weighing 0.1 g and having atomic mass 51 reacted with dilute H₂SO₄ to give 43.9 ml of hydrogen at 0°C and 1 atm. The solution containing the metal in this lower oxidation state was

Question

A polyvalent metal weighing 0.1 g and having atomic mass 51 reacted with dilute H₂SO₄ to give 43.9 ml of hydrogen at 0°C and 1 atm. The solution containing the metal in this lower oxidation state was found to require 58.8 ml of 0.1 N-permanganate for complete oxidation. What are the valencies of the metal?

TestHub · Accepted Answer

mol H₂ = 43.9/22400 = 1.96 mmol; mol metal = 0.1/51 = 1.96 mmol, so 1 mol H₂ per mol metal and the lower valency is 2. meq KMnO₄ = 58.8 x 0.1 = 5.88; electrons per metal atom = 5.88/1.96 = 3, so the higher valency is 2 + 3 = 5. Valencies 2 and 5, option (a).

Chemistry - Redox Reactions Question with Solution | TestHub

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