An acidic solution of dichromate is electrolyzed for 8 minutes using 2 A current. As per the following equation
${Cr}_{2}{O}_{7}^{2} + 14{H}^{+} + 6{e}^{-} \to 2{Cr}^{3 +} + 7{H}_{2}O$
The amount of ${Cr}^{3 +}$ . obtained was $0 . 104g$ . The efficiency of the process $( in % )$ is (Take : $F = 960000C$ , At. mass of chromium $= 52$ )

Question

An acidic solution of dichromate is electrolyzed for 8 minutes using 2 A current. As per the following equation

${Cr}_{2}{O}_{7}^{2} + 14{H}^{+} + 6{e}^{-} \to 2{Cr}^{3 +} + 7{H}_{2}O$
The amount of ${Cr}^{3 +}$ . obtained was $0 . 104g$ . The efficiency of the process $( in % )$ is (Take : $F = 960000C$ , At. mass of chromium $= 52$ )

Quantrex Academy · Accepted Answer

Correct answer: 60

Charge (q) = it = 2 × 8 × 60 = 960C (960)/(96000) = 0 . 01F Cr _ 2 O _ 7 ^ 2 - + 14 H ^ + + 6 e ^ - → 2 Cr ^ 3 + + 7 H _ 2 O 0 . 01F(1)/(3) × 0 . 01mole Theoritical mass of Cr ^ 3 + = (1)/(3) × (600)/(96000) × 52 = 0 . 173g So, efficiency = W _ actual W _ Theoritial × 100 = (0 . 104)/(0 . 173) × 100 = 60 %

An acidic solution of dichromate is electrolyzed for 8 minutes...

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