Question

Given,13.5g of Al gets deposited when electricity is passed through the solution of $AlC{{l}_{3}}$. The number of faraday used are:
0.50
1.00
1.50
2.00

Answer 1

Before solving this question, we should first know about faraday’s law. It is a law that states that the chemical that is deposited because of the flow of current through an electrolyte is directly proportional to the quantity of electricity in coulombs passed through it.

Complete answer:
$AlC{{l}_{3}}$ known as aluminum trichloride. It contains aluminum and chloride in a 1:3 ratio. It is a white solid but due to the contamination of samples with iron(III) chloride, it gives yellow color.
When we dilute any electrolyte in the water, its molecules break down into cations (positive ions) and anions (negative ions). The cations move to the electrode that has a negative terminal of the battery and these cations take electrons from it to become a metal atom and to be deposited on the electrode.
Faraday’s First law of electrolysis –
$m\propto quantity\,of\,electricity$
m = ZQ
In this, Z is the constant and is called an electrochemical equivalent.
Let’s solve the numerical-
According to Faraday’s First law of electrolysis
mass given is 13.5g
Charge =?
$A{{l}_{3}}+3{{e}^{-}}\to Al$
${{n}_{f}}=3$
1 mole of Al $\to$27
$Q=n\times {{n}_{f}}$
$n=\dfrac{mass}{molar\,mass}$
$n=\dfrac{13.5}{27}$
$Q=\,\dfrac{13.5}{27}\times 3$
= 1.5 F

So, Option (C) 1.50 F is correct.

Note:
If we put the value of Q as 1 in the equation, then Z will become equal to m. This shows that the Z (electrochemical equivalent) of any substance is the amount of it deposited when 1 coulomb of charge is passed through the solution. It is generally expressed in milligrams per coulomb or kilogram per coulomb.