The standard electrode potential of M⁺ / M in aqueous solution does not depend on

Solution

Chemistry ma’am · 3 steps

Break M(s) to M+(aq) into its real steps. Atoms are ionised only after they are in the gas phase.

1. Build a cycle. The electrode potential of M⁺/M reflects the energy change for M(s) → M⁺(aq) + e⁻. We split this conversion into simple steps whose energies we know.

   M(s) →(Δ_(sub)H) M(g) →(IE) M⁺(g) →(Δ_(hyd)H) M⁺(aq)

   Step	Change	In the cycle?
   Sublimation	M(s) → M(g)	Yes
   Ionisation of gaseous atom	M(g) → M⁺(g) + e⁻	Yes
   Hydration of gaseous ion	M⁺(g) → M⁺(aq)	Yes
   Ionisation of solid atom	M(s) → M⁺(s)	No

2. Why not. Ionisation enthalpy is defined only for an isolated gaseous atom. A solid metal must first sublime, and only then is the free atom ionised.
3. So. The electrode potential does not depend on the ionisation of a solid metal atom, which is option (c).

The idea to keep. Electrode potential comes from three steps: sublimation, ionisation of the gaseous atom, and hydration of the gaseous ion. Ionisation always happens in the gas phase.

Answer from the NTA final answer key. Solution by PrepWiser.