Chemistry · Unit 3 · Chemical equilibrium systems · Chemical equilibrium
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A chemist prepares a solution by dissolving sodium hydroxide (NaOH) in water. The hydroxide ion concentration is measured as \(2.50 \times 10^{-3}\) mol L\(^{-1}\) at 298 K. Analyse the data to determine the hydrogen ion concentration, \([\text{H}^{+}]\), in the solution.
A weak acid, HA, has an acid dissociation constant \(K_a = 1.8 \times 10^{-5}\) at 298 K. A solution of this acid is prepared with an equilibrium hydronium ion concentration of \([\text{H}_3\text{O}^+] = 4.0 \times 10^{-3}\) mol L\(^{-1}\) and an equilibrium conjugate base concentration of \([\text{A}^-] = 4.0 \times 10^{-3}\) mol L\(^{-1}\). Analyse the data to determine: (a) the equilibrium concentration of the undissociated acid, \([\text{HA}]\) (b) the pH of the solution.
A weak acid, HA, has an acid dissociation constant (\(K_a\)) of \(1.8 \times 10^{-5}\). At equilibrium, an aqueous solution of HA has a hydronium ion concentration of \(3.0 \times 10^{-3}\) mol L\(^{-1}\) and a conjugate base concentration of \(3.0 \times 10^{-3}\) mol L\(^{-1}\). Analyse the data to determine the equilibrium concentration of the undissociated acid HA.