Given the following notation for an electrochemical cell Pt (s) | H2 (g) | H + (aq) || Ag + (aq) | Ag (s) what is the balanced overall (net) cell reaction?

H₂ (g) + 2Ag⁺ (aq) → 2Ag (s) + 2H⁺ (aq)

Explanation:

In an electrochemical cell, the cell notation is written in a way, that first is the oxidation half is written followed by the reduction, which are separated by the salt bridge,

hence, from the question, the cell notation is given as -

Pt (s) | H₂ (g) | H⁺ (aq) || Ag⁺ (aq) | Ag (s)

Hence, from the above reaction, the oxidation half cell and reduction half cell as given as -

Oxidation -

H₂ (g) → H⁺ (aq)

Reduction -

Ag⁺ (aq) → Ag (s)

Now, balancing the reaction, by adding electrons on the required side -

Oxidation -

H₂ (g) → 2H⁺ (aq) + 2e⁻

Reduction -

Ag⁺ (aq) + e⁻ → Ag (s)

The above reaction can also be written as -

2Ag⁺ (aq) + 2e⁻ → 2Ag (s)

Now, to overall cell reaction can be written as adding the respective half cells and eliminating the electrons, i. e.,

H₂ (g) + 2Ag⁺ (aq) → 2Ag (s) + 2H⁺ (aq)