Calculate dissociation constants (Ka, Kb, and Kw), pKa, pKb, and the concentrations of reactants and products. (Formula: 𝐾a = [H3O+][A−] [HA]; 𝐾b = [BH+][OH−] [B]; 𝐾𝑤 = 𝐾a × 𝐾b)

Question 1

Question 1

A weak acid HA has a dissociation constant $K_a = 1.8 \times 10^{-5}$ at 298 K. Calculate $\mathrm{p}K_a$ for this acid.

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Question 2

Question 2

A 0.100 mol L⁻¹ aqueous solution of ammonia (NH₃) has a base dissociation constant (Kb) of 1.8 × 10⁻⁵ at 25 °C. Calculate the concentration of hydroxide ions, [OH⁻], in this solution. Show your working.

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Question 3

Question 3

Propanoic acid (C₂H₅COOH) is a weak acid with a Ka value of 1.3 × 10⁻⁵ at 25 °C. (a) Calculate the pKa of propanoic acid. (b) Using the relationship Kw = Ka × Kb, calculate the Kb value for the propanoate ion (C₂H₅COO⁻) at 25 °C, given that Kw = 1.0 × 10⁻¹⁴.

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Question 4

Question 4

Determine the pKb of ammonia (NH₃) given that its base dissociation constant is Kb = 1.8 × 10⁻⁵.

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Calculate dissociation constants (Ka, Kb, and Kw), pKa, pKb, and the concentrations of reactants and products. (Formula: 𝐾a = [H3O+][A−] [HA]; 𝐾b = [BH+][OH−] [B]; 𝐾𝑤 = 𝐾a × 𝐾b)

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