Question

What is the value of Faraday number in SI units?
$\begin{align}
  & A.9.65coulombk{{g}^{-1}}-equivalent \\
 & B.9.65\times {{10}^{7}}coulombk{{g}^{-1}}-equivalent \\
 & C.9.65\times {{10}^{-7}}coulombk{{g}^{-1}}-equivalent \\
 & D.9.65coulomb{{g}^{-1}}-equivalent \\
\end{align}$

Answer 1

Hint: Faraday is given as the indication to the charge of one mole of electron. It is denoted as the symbol $F$. It can be found by taking the product of Avogadro number and the charge of an electron. These all may help you to solve this question.
Formula used:
$F=e{{N}_{A}}$
Where $e$ be the charge of an electron and ${{N}_{A}}$ be the Avogadro number.

Complete answer:
Avogadro number is expressed as the value which is given as,
${{N}_{A}}=6.022\times {{10}^{23}}$
This value of the number is denoting the number of electrons in one mole of molecules.
And also the charge of the electron in coulomb is calculated using the value which is also a constant given as,
$e=1.60217646\times {{10}^{-19}}C$
So according to the definition of the faraday constant, the value of the constant is given as the product of the Avogadro number and the charge of an electron. Therefore this can be written as,
$F=e{{N}_{A}}$
Substituting the values in it will give the value of one farad.
That is,
$F=e{{N}_{A}}={{1.6021764610}^{-19}}\times 6.022\times {{10}^{23}}$
Simplifying this equation can be written as,
$F=9.65\times {{10}^{4}}C{{g}^{-1}}-equivalent$
It is mentioned in the question that we have to calculate the SI unit of one farad. This can be obtained when the gram is converted into kilograms.
As we all know, I gram can be written in the form of kilogram as,
$1g={{10}^{-3}}kg$
So let us apply this in the value of the faraday number.
\[\begin{align}
  & F=\dfrac{9.65\times {{10}^{4}}}{{{10}^{-3}}}C{{g}^{-1}}-equivalent \\
 & F=9.65\times {{10}^{7}}Ck{{g}^{-1}}-equivalent \\
\end{align}\]

So, the correct answer is “Option B”.

Note:
One of the most general uses of the Faraday constant is made in electrolysis. Dividing the quantity of charge in coulombs by the Faraday constant will result in the amount in moles of elements which is to be oxidized. This constant was named after the scientist Michael Faraday.