Write the chemical reaction for hydrogen thiocyanate in water, whose equilibrium constant is Ka. Include the physical states for each species

Write the chemical reaction for thiocyanate ion in water, whose equilibrium constant is Kb. Include the physical states for each species

HSCN (aq) + H₂O (l) ⇄ SCN⁻ (aq) + H₃O⁺ (aq) Ka

SCN⁻ (aq) + H₂O (l) ⇄ HSCN (aq) + OH⁻ (aq) Kb

Explanation:

We identify the formula:

HSCN → hydrogen thiocyanate which is also known as Thiocyanic acid

HSCN (aq) + H₂O (l) ⇄ SCN⁻ (aq) + H₃O⁺ (aq) Ka

As an acid, it gives proton to the solution. It is a weak acid, because the Ka

Ka = [SCN⁻]. [H₃O⁺] / [HSCN]

As a weak acid, the thiocyanate ion, will be the conjugate strong base. In water It can make hydrolisis:

SCN⁻ (aq) + H₂O (l) ⇄ HSCN (aq) + OH⁻ (aq) Kb

As a base, it takes a proton from water.

Kb = [HSCN]. [OH⁻] / [SCN⁻]