Sodium dithionite, Na2S2O4, is oxidised completely to sulfate, SO4^2-. What mass of dithionite loses 0.060 mol of electrons? (Na 23, S 32, O 16.) Give two decimal places.

JEE Advanced levelNumerical answerDifficulty 3 of 3rx050

Sodium dithionite, $Na X_{2} S X_{2} O X_{4}$ , is oxidised completely to sulfate, $SO X_{4} X^{2 -}$ . What mass of dithionite loses $0.060$ mol of electrons? (Na 23, S 32, O 16.) Give two decimal places.

Numerical answer type, answer in g, tolerance 0.01.

S in

S X_{2} O X_{4} X^{2 -}

+ 3

and in sulfate

+ 6

, so each formula unit loses

2 \times 3 = 6

electrons. Moles

= 0.060/6 = 0.010

. Molar mass

= 46 + 64 + 64 = 174

, so mass

= 0.010 \times 174 = 1.74 g