Question

The EMF of the cell is $0.36\;{\text{V}}$.The RHE is known as calomel electrode and its standard electrode potential is +0.242V. Find the ${{\mathbf{H}}^ \oplus }$ ions concentration in LHE and hence find the pH of LHE.

Answer 1

The maximum potential difference between two electrodes of a cell is known as the electromotive force of a cell, or EMF of a cell. It's also known as the net voltage between the half-reactions of oxidation and reduction. An electrochemical cell's EMF is primarily used to decide whether it is galvanic or not.
Formula used:
Nernst Equation
$E = {E^0} - \dfrac{{RT}}{{zF}}\ln Q$
E is the Reduction potential
${E^0}$ stands for Standard potential
R stands for universal gas constant
T stands for temperature (K)
z stands for ion charge
F stands for Faraday constant
Q stands for reaction quotient

Complete answer: An electrode is a solid electric conductor that conducts electricity through non-metallic solids, liquids, fluids, plasmas, and vacuums. Electrodes are usually strong conductors of electricity, so they don't have to be made of silicon. Anode and cathode are two different types of electrodes.
The saturated calomel electrode is dependent on the reaction between elemental mercury and mercury(I) chloride as a reference electrode. The silver chloride electrode has largely replaced it, but the calomel electrode has a reputation for being more durable.
The Nernst equation is an electrochemical equation that relates an electrochemical reaction's reduction potential (half-cell or full-cell reaction) to the normal electrode potential, temperature, and activities (often approximated by concentrations) of the chemical species undergoing reduction and oxidation. Walther Nernst, a German physical chemist who devised the equation, was given the name.
Given ${{\mathbf{E}}_{{\text{cell }}}} = {\mathbf{0}}.{\mathbf{36V}}$
${\mathbf{E}}_{{\text{cell }}}^{{ \ominus _{{\text{cel }}}}} = {\mathbf{E}}_{\left( {{\text{C}}{{\text{l}}^ \ominus }\left| {{\text{H}}{{\text{g}}_2}{\text{C}}{{\text{l}}_2}} \right|\mid {\text{Hg}}} \right)}^ \ominus - {\mathbf{0}} = {\mathbf{0}}.{\mathbf{242V}}$
Substituting these values in Nernst equation
$\Rightarrow 0.36 = 0.242 - \dfrac{{0.059}}{1}\log \dfrac{{\left[ {{{\text{H}}^ \oplus }} \right]}}{{\left[ {{\text{p}}_{\left. {{{\text{H}}_2}} \right]}^{1/2}} \right.]}}$
$\Rightarrow - {\mathbf{0}}.{\mathbf{118}} = - {\mathbf{0}}.{\mathbf{059}}\log \left[ {{{\mathbf{H}}^ \oplus }} \right]$
$\Rightarrow - \log \left[ {{{\mathbf{H}}^ \oplus }} \right] = {\mathbf{pH}}\dfrac{{{\mathbf{0}}.{\mathbf{110}}}}{{{\mathbf{0}}.{\mathbf{059}}}} = {\mathbf{2}}$
pH = 2

Note:
pH is a measure used in chemistry to describe the acidity or basicity of an aqueous solution. The pH in acidic solutions is lower than that of basic or alkaline solutions. The pH scale is logarithmic, indicating the concentration of hydrogen ions in a solution in inverse order.