Cl+Mg

Most likely you’re asking about the reaction of chlorine with magnesium to form magnesium chloride.

• Balanced equation (chlorine as Cl2 gas reacting with Mg metal): Mg(s) + Cl2(g) → MgCl2(s)

• Redox half-reactions:

  • Oxidation: Mg → Mg2+ + 2 e−
  • Reduction: Cl2 + 2 e− → 2 Cl−
  • Net: Mg + Cl2 → MgCl2

• If you start from chlorine atoms (Cl, not Cl2): you’d need two Cl atoms per Mg to make MgCl2, i.e., Mg + 2 Cl → MgCl2, and the two Cl atoms would pair to form Cl2 if they source from diatomic chlorine.

• Standard potentials (optional thermodynamics):

  • Cl2 + 2 e− ⇌ 2 Cl−, E° ≈ +1.36 V
  • Mg2+ + 2 e− ⇌ Mg(s), E° ≈ −2.37 V
  • E°cell for Mg + Cl2 → MgCl2 ≈ 1.36 − (−2.37) ≈ +3.73 V This indicates a highly spontaneous reaction.

• Enthalpy (typical for forming solid MgCl2): ΔH°rxn ≈ −641 kJ per mole of MgCl2 formed (formation of MgCl2(s)). Values can differ if you form hydrated MgCl2 or MgCl2 in a different phase.

If you want, tell me which specifics you need (balanced equation with states, thermodynamics like ΔH° or E°cell, or something else) and I’ll tailor it to your syllabus.