How many moles of electrons are needed to deposit 0.4 mol of sodium from Na⁺?

A) 0.8 mol e⁻

B) 1.4 mol e⁻

C) 0.4 mol e⁻

D) 1.2 mol e⁻

Answer: C

Explanation: Each Na⁺ ion requires 1 electron(s) to form one metal atom. 0.4 mol metal therefore needs 0.4 × 1 = 0.4 mol electrons.