Chemistry – Inorganic chemistry | e-Consult

MgO is an ionic compound formed through the electrostatic attraction between Mg²⁺ cations and O^2- anions. The bonding is a result of the transfer of electrons from magnesium to oxygen, creating these ions.

MgO has high melting and boiling points due to the strong electrostatic forces between the ions in the crystal lattice. These forces are non-directional, meaning they act equally in all directions, requiring a large amount of energy to overcome. The high charge of the ions (Mg²⁺ and O^2-) also contributes to the strength of the electrostatic attraction.

Reaction with Water: MgO reacts with water, although slowly, to produce magnesium hydroxide (Mg(OH)₂). This is an endothermic reaction.

MgO(s) + H₂O(l) ⇌ Mg(OH)₂(aq)

Reaction with Dilute Acids: MgO reacts with dilute acids (e.g., HCl, H₂SO₄) to produce magnesium salts and water. This is a neutralization reaction.

MgO(s) + 2HCl(aq) → MgCl₂(aq) + H₂O(l)

The reaction with acid involves the protonation of the oxide ion (O^2-) to form hydrogen peroxide (H₂O₂), which then decomposes into water and oxygen. This is why heat is released.