Bismuth(III) hydroxide is reduced to black metallic bismuth by sodium stannite: 2Bi(OH)3 + 3Na2SnO2 -> 2Bi + 3Na2SnO3 + 3H2O. The number of moles of stannite consumed per mole of Bi(OH)3 is

JEE Main levelSingle correct optionDifficulty 2 of 3qc173

Bismuth(III) hydroxide is reduced to black metallic bismuth by sodium stannite: $2 Bi (OH) X_{3} + 3 Na X_{2} SnO X_{2} 2 Bi + 3 Na X_{2} SnO X_{3} + 3 H X_{2} O$ . The number of moles of stannite consumed per mole of $Bi (OH) X_{3}$ is

Bi(III) to Bi(0) takes 3 electrons; Sn(II) to Sn(IV) gives 2 electrons per stannite. Moles of stannite =

3/2 = 1.5

per mole of

Bi (OH) X_{3}

, as the balanced equation (3 stannite for 2 Bi) shows.