Which of the following anions has a valency of -3?

Correct option is A

The Correct answer is (a) Nitride. The nitride anion (N³⁻) has a valency of -3. Nitride is formed when nitrogen gains three electrons to complete its outer electron shell, resulting in a charge of -3. This makes it trivalent, meaning it can combine with three positive charges to form compounds. Nitrate (NO₃⁻) has a valency of -1. Sulphide (S²⁻) has a valency of -2. Sulphate (SO₄²⁻) has a valency of -2. Information Booster: • Nitride ions are commonly found in compounds such as aluminum nitride (AlN) and magnesium nitride (Mg₃N₂). • Nitride compounds are generally quite stable and are often used in materials science due to their hardness and high melting points. • Nitrides are less common than nitrates and sulfates in nature but have important industrial applications. • Nitride ions can form ionic compounds with metals, leading to various industrial applications.