Write the equilibrium expression for the following reactions: 1. 4NH3 (g) + 5O2 (g) ↔ 4NO (g) +6H2O (g)
2. ZrI4 (s) ↔ Zr (s) + 2I2 (g)
3. NH3 (g) + HCl (g) ↔ NH4Cl (s)

1. Kc = [NO]⁴ [H₂O]⁶ / [NH₃]⁴ [O₂]⁵

2. Kc = [I₂]²

3. Kc = 1/[NH₃] [HCl]

Explanation:

The equilibrium constant (Kc) is equal to the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactant raised to their stoichiometric coefficients. It only includes gases and aqueous species.

1. 4 NH₃(g) + 5 O₂(g) ↔ 4 NO(g) + 6 H₂O(g)

Kc = [NO]⁴ [H₂O]⁶ / [NH₃]⁴ [O₂]⁵

2. ZrI₄(s) ↔ Zr(s) + 2 I₂(g)

Kc = [I₂]²

3. NH₃(g) + HCl(g) ↔ NH₄Cl(s)

Kc = 1/[NH₃] [HCl]

4d^55s^1 ( third choice)