M5S8 – Acid Base Equilibria 2

The indicator thymol blue changes from yellow to blue of the pH range 8.0 to 9.6. The indicator could be used to detect accurately the end-point in a titration of roughly 0.1 mol dm^-3 solutions of:

(i) ethanoic acid with sodium hydroxide

(ii) hydrochloric acid with ammonia

(iii) hydrochloric acid with sodium hydroxide

(iv) ethanoic acid with ammonia

Which of these compounds give an alkaline solution when mixed with water?

(i) NH₄Cl

(ii) NH₃

(iii) CH₃CH₂OH

(iv) CH₃CO₂Na

Which of these are examples of acid-base reactions according to the Bronsted-Lowry theory.

(i) ZnO_(s)+2H₃O⁺_(aq)->Zn²⁺_(aq)+3H₂O_(l)

(ii) H₂O_(l)+H₂O_(l)->H₃O⁺ _(aq)+ OH^-_(aq)

(iii) NH_3(g)+HBr_(g)->NH₄Br _(s)

(iv) SO_2(g)+H₂O_(l)->H₂SO_3(aq)

pH = 2.9 for a solution which contains equal concentrations of chlorethanoic acid and sodium chlorethanoate. What is the pH of the solution after mixing it with twice its own volume of pure water?

The value of K_a for ethanoic acid = 1.7 x 10^-5 mol dm^-3 (pK_a = 4.8). During a titration of 20.0cm³ 0.1 mol dm^-3 solution of ethanoic acid with 0.1 mol dm^-3 sodium hydroxide, what is the pH of the mixture in the flask after adding 10.0 cm³ of the alkali?

What is the pH of a 0.01 mol dm^-3 solution of methanoic acid given that for this acid: K_a = 1.6 x 10^-4 mol dm^-3 at 298K ?

Why does the term [H₂O_(l)]not appear in the expression for K_a for methanoic acid?

What is the pH of a 0.01 mol dm^-3 solution of sodium hydroxide given that Kw = 1.0 x 10^-14 mol²dm^-6 at 298K?

What is the hydrogen ion concentration in an aqueous solution if the pH = 3.0?

What is the conjugate acid of HSO₄^-?