Question

14. Given equal concentrations of the following acids, which exhibits the greatest amount of ionization in water? (3 pts) A) nitrous acid B) chlorous acid C) ascorbic acid D) hydrobromic acid E) citric acid 15. Which solution has the highest pH? (3 pts) A) 0.10 M HBr(aq) B) 0.10 M HI (aq) C) 0.10 MHF (aq) D) 0.10 M HCl(aq) E) 0.10 M HClO4(aq) 16. Which of the following solutes, dissolved in 1.0 kg of water, would be expected to provide the fewest particles and to freeze at the highest temperature? (3pt) A) 0.10 mol HCIO B) 0.10 mol HCIO3 C) 0.10 mol HCIO2 D) 0.10 mol HCIO4 E) 0.10 mol HCI

Answer 1

1. At equal concentrations, the amount of ionization of an acid depends on the K_a values of the acids, i.e. the ionization constant of the acid. Since, HBr completely dissociates and has a K_a value >1, thus, in the aqueous medium, it exhibits the highest degree of ionization in water.

2. Weaker the acid, higher the pH. In the given list of acids, all the acids apart from HF, have K_a values > 1, thus, are strong acids, where as K_a for HF = 6.6 x 10^-4. Thus, its pH value would be the highest.

3. More the number of particles in a solution, lower is the freezing point. In the given list of acids, HClO₄ and HCl are strong acids and HClO being the weakest. Thus, for same concentrations, HClO would not dissociate completely into ions and increase the freezing point.