Question

How many moles of $Pt$ may be deposited on the cathode when $0.80$F of electricity is passed through a $1.0$M solution of $P{t}^{4+}$?

• A. $0.1$ mol
• B. $0.2$ mol
• C. $0.4$ mol
• D. $0.6$ mol

Answer 1

Answer: (B)

$0.2$ mol

Faraday's First Law of Electrolysis states that only, According to this law, the chemical deposition due to the same flow of current through an electrolyte is directly proportional to the quantity of electricity (coulombs) passed through it.

We have the reaction,

$P{t}^{4+}+4e^{-}\to Pt$

So, 4 moles of electricity or $4F$ of electricity is required to deposit 1 mole of $Pt$

$⟹$0.80F of electricity will deposit $\frac{1}{4}\times 0.80=0.20$ $mol$