Calculate the ph and the poh of each of the solutions at 25

Question

1. Calculate the pH and the pOH of each of the following solutions at 25 °C for which the substances ionize completely:

(a) 0.200 M HCl

(b) 0.0143 M NaOH

(c) 3.0 M HNO₃

(d) 0.0031 M Ca(OH)₂

2. What is the ionization constant at 25 °C for the weak acid (CH₃)₂NH₂⁺, the conjugate acid of the weak base (CH₃)₂NH, K_b = 7.4 × 10^-4?

3. Which of the following will increase the percent of HF that is converted to the fluoride ion in water?

(a) addition of NaOH

(b) addition of HCl

(c) addition of NaF

4. Calculate the ionization constant for each of the following acids or bases from the ionization constant of its conjugate base or conjugate acid:

(a) F^-

(b) NH₄⁺

(c) AsO₄^3-

(d) (CH₃)₂NH₂⁺

(e) NO₂^-

(f) HC₂O^4-(as a base)

5. Determine whether aqueous solutions of the following salts are acidic, basic, or neutral:

(a) Al(NO₃)₃

(b) RbI

(c) KHCO₂

(d) CH₃NH₃Br

6. What is [H₃O⁺] in a solution of 0.075 M HNO₂ and 0.030 M NaNO₂?

HNO₂(aq) + H₂O(l) ? H₃O⁺(aq) + NO₂^-(aq)                            K_a = 4.5 × 10^-5

7. Calculate the pH of a buffer solution prepared from 0.155 mol of phosphoric acid, 0.250 mole of KH₂PO₄, and enough water to make 0.500 L of solution.

8. Draw a curve similar to that shown in Figure for a series of solutions of NH₃. Plot [OH^-] on the vertical axis and the total concentration of NH₃ (both ionized and nonionized NH₃ molecules) on the horizontal axis. Let the total concentration of NH₃ vary from 1 × 10^-10 M to 1 × 10^-2 M.