Question

16) The molar concentration of hydronium ion in pure water at 25°C is 1.0 x 10 b) 0.00 c) 1.0 x 1014 d) 1.0 e) 7.00 17) A solution is prepared by dissolving 0.23 mol of hydrazoic acid and 0.27 mol of sodium azide in water sufficient to yield 1.00 L of solution. The addition of 0.05 mol of NaOH to this buffer solution causes the pH to increase slightly. The pH does not increase drastically because the NaOH reacts with the the buffer solution. The K, of hydrazoic acid is 1.9 x 10 present in a) H2O b) H2o sodium azide hydrozoic acid e) This is a buffer solution; the pH does not change upon addiction of acid or base.

Answer 1

- 16) The molar concentration of hydronium ion in pure water at 25°C is a) 1.0 x 10 b) 0.00 c) 1.0 x 10 14 d) 1.0 e) 7.00 At 25 0C, the ionic product of pue water, [H3O+] [OH-] = 1*10^-14 but for pure water, [H3O+] = [OH-] [H3O+] [H3O+] = 1*10^-14 ======> [H3O+] = 1*10^-7 Therefore, molar concentration of hydronium ion is 1*10^-7 17) A solution is prepared by dissolving 0.23 mol of hydrazoic acid and 0.27 mol of sodium azide in water sufficient to yield 1.00 L of solution. The addition of 0.05 mol of NaOH to this buffer solution causes the pH to increase slightly. The pH does not increase drastically because the NaOH reacts with the present in the buffer solution. The K, of hydrazoic acid is 1.9 x 10" a) H2O The given buffer is a mixture of hydrazoic acid (weak acid) and sodium b) H30* benzoate (conjugate base). The added NaOH being a base it reacts sodium azide with the acid of the buffer solution i.e with hydrazoic acid hydrozoic acid e) This is a buffer solution, the pH does not change upon addiction of acid or base.