Electrochemistry Ques 10

10. The number of Faradays $(F)$ required to produce $20 g$ of calcium from molten $CaCl_2$ (Atomic mass of $Ca=40 g mol^{-1}$ ) is:

[2020]

(a) 2

(b) 3

(c) 4

(d) 1

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Answer:

Correct Answer: 10.(d)

Solution:

(d) 1 equivalent of any substance is deposited by $1 F$ of charge.

$20 g$ calcium contains,

Number of equivalents $=\frac{\text{ Given mass }}{\text{ Equivalent mass }}$

(Equivalent mass of $Ca =\frac{\text{ Atomic mass }}{\text{ Valency }}=\frac{40}{2}=20) $

$ =\frac{20}{20}=1 $

So, 1 Faraday of charge is required to deposit 1 equivalent of $Ca$.