The pressure of H2 required to make the potential of H2 -electrode zero in pure water at 298 K is

To determine the pressure of H2 required to make the potential of the H2-electrode zero in pure water at 298 K, we can use the Nernst equation. The Nernst equation relates the electrode potential to the concentration of the species involved.

The Nernst equation is given as:

E = E° - (RT/nF) * ln(Q)

Where: E is the electrode potential E° is the standard electrode potential R is the gas constant (8.314 J/(mol·K)) T is the temperature in Kelvin (298 K in this case) n is the number of electrons transferred in the reaction F is the Faraday constant (96485 C/mol) ln is the natural logarithm Q is the reaction quotient

In this case, we want to make the potential of the H2-electrode zero, so E = 0. The standard electrode potential for the H2-electrode is 0 V.

Therefore, the Nernst equation simplifies to:

0 = 0 - (RT/nF) * ln(Q)

Since we are dealing with pure water, the reaction quotient Q can be expressed as the concentration of H2 gas, which is equal to the pressure of H2 divided by the standard pressure (1 atm).

So, we can rewrite the equation as:

0 = 0 - (RT/nF) * ln(P_H2/1)

Simplifying further:

0 = - (RT/nF) * ln(P_H2)

To solve for the pressure of H2 (P_H2), we rearrange the equation:

ln(P_H2) = 0

Taking the exponential of both sides:

P_H2 = e^0

P_H2 = 1 atm

Therefore, the pressure of H2 required to make the potential of the H2-electrode zero in pure water at 298 K is 1 atm.