For the reaction 2 Cr(s) + 3 Pb²⁺(aq) ⟶ 3 Pb(s) + 2 Cr³⁺(aq), what is the value of n in the Nernst equation?

The value of n is 6

Explanation:

The half-reactions of the problem are:

Cr(s) → Cr³⁺ + 3e⁻

Pb²⁺ + 2e⁻→ Pb(s)

To balance the electrons we must multiply the half-reactions as follows:

2 * (Cr(s) → Cr³⁺ + 3e⁻)

3 * (Pb²⁺ + 2e⁻→ Pb(s))

2Cr(s) → 2Cr³⁺ + 6e⁻

3Pb²⁺ + 6e⁻→ 3Pb(s)

In Nernst equation, the value of n are the electrons used to balance the reaction, as in this problem, the electrons are 6:

a electronegativity decreases beacuse the size of nucleus is bigger.

the answer is c. nacl