The number of Faradays ($F$) required to produce $20g$ of calcium from molten $CaC{l}_2$ (Atomic mass of $Ca=40gmo{l}^{–1}$) is:

The correct option is C $1$
$CaC{l}_2\to C{a}^{2+}+2C{l}^{-}$
According to the above reaction,$C{a}^{2+}$ is formed from molten $CaC{l}_2$:
$C{a}^{2+}(aq.)$ + $2e-$ ⟶ $Ca\left(aq\right)$
$2F$ $(1mole=40g$)
$1F$ $20g$
Thus, one Faraday is required to produce $20g$ of calcium from molten $CaC{l}_2$.
Hence, option c is correct