Question

How many faradays are required to reduce $1\, mol$ of $Cr_{2} O_{7}^{2-}$ to $Cr^{3+}$ in acid medium?

• A. 2
• B. 3
• C. 5
• D. 6

Answer 1

Answer: (D)

6

Answer 2

$Cr _{2} O _{7}^{2-} \longrightarrow Cr ^{3+}$ Change in $+3$
Oxino. $=+6$
Total change in number of electrons
$=2 \times 3=6$ mole $=6 F$