Use Na = 23, S = 32, O = 16, K = 39, Mn = 55. In acidic medium, MnO4- oxidises sulfite to sulfate. The mass of KMnO4 needed to oxidise 6.3 g of Na2SO3 is:

JEE Main levelSingle correct optionDifficulty 2 of 3rx128

Use Na = 23, S = 32, O = 16, K = 39, Mn = 55. In acidic medium, $MnO X_{4} X^{-}$ oxidises sulfite to sulfate. The mass of $KMnO X_{4}$ needed to oxidise $6.3 g$ of $Na X_{2} SO X_{3}$ is:

SO X_{3} X^{2 -} SO X_{4} X^{2 -}

has

n = 2

MnO X_{4} X^{-}

has

n = 5

, so

n (KMnO X_{4}) = (2/5) n (Na X_{2} SO X_{3})

n (Na X_{2} SO X_{3}) = 6.3/126 = 0.05

, so

KMnO X_{4}

= 0.02 mol

= 0.02 \times 158 = 3.16 g