Use Na = 23, S = 32, O = 16 and molar volume 22.4 L/mol at STP. Chlorine oxidises thiosulfate completely to sulfate: S2O3^2- + 4Cl2 + 5H2O -> 2SO4^2- + 8Cl- + 10H+. The volume of Cl2 at STP needed for 15.8 g of Na2S2O3 is:

JEE Advanced levelSingle correct optionDifficulty 3 of 3rx147

Use Na = 23, S = 32, O = 16 and molar volume $22.4 L/mol$ at STP. Chlorine oxidises thiosulfate completely to sulfate: $S X_{2} O X_{3} X^{2 -} + 4 Cl X_{2} + 5 H X_{2} O 2 SO X_{4} X^{2 -} + 8 Cl X^{-} + 10 H X^{+}$ . The volume of $Cl X_{2}$ at STP needed for $15.8 g$ of $Na X_{2} S X_{2} O X_{3}$ is:

n (Na X_{2} S X_{2} O X_{3}) = 15.8/158 = 0.1

. From the equation, 4 mol

Cl X_{2}

per mol thiosulfate (

n

-factor 8,

Cl X_{2}

has 2), so

n (Cl X_{2}) = 0.4

. Volume

= 0.4 \times 22.4 = 8.96 L