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 ^ - 2 Cr ^ 3+ +7 H _ 2 O The amount of Cr ^ 3+ obtained was 0.104 , g. The efficiency of the process(in %) is (Take : F =96000 , C, At. mass of chromium =52 )

An acidic solution of dichromate is electrolyzed for 8 minutes us…

MCQ

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

$Cr _{2} O _{7}^{2-}+14 H ^{+}+6 e ^{-} \rightarrow 2 Cr ^{3+}+7 H _{2} O$

The amount of $Cr ^{3+}$ obtained was $0.104\, g$. The

efficiency of the process(in\%) is

(Take : $F =96000\, C$, At. mass of chromium $=52$ )

✓

Correct option: A.

$60$

a
Moles of $e ^{\ominus}=\left(\frac{8 \times 60 \times 2}{96000}\right)$

Using stoichiometry; theoritically

$\frac{ n _{ e ^{\ominus}} used }{6}=$$\frac{ n _{ cr ^{+3}} \text {produced }}{2}$

$\Rightarrow n _{ cr ^{+3}}$ produced $=\frac{2}{6} \times \frac{8 \times 60 \times 2}{96000}$

$=\frac{0.02}{6}$

$\Rightarrow wt _{ cr ^{+3}}$ theoritically produced

$=\left(\frac{0.02}{6} \times 52\right) g$

$\Rightarrow \%$ efficiency $=\frac{0.104 g }{\left(\frac{0.02 \times 52}{6}\right) g } \times 100$

$=60 \%$

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