AP Chemistry Review - Chapter 17

Calculate the pH of a solution that is 0.278 M in sodium formate NaHCO₂ (strong electrolyte) and 0.222 M in formic acid HCO₂H (weak acid). The K_a of formic acid is 1.77 x 10^-4.

The addition of hydrofluoric acid and _________ to water produces a buffer solution.

HF

NaF

NaBr

KI

NaNO₃

What is the pH of a buffer solution that is 0.172 M in hypochlorous acid HClO (weak acid) and 0.131 M in sodium hypochlorite (strong electrolyte)? The K_a of hypochlorous acid is 3.8 x 10^-8.

A solution is prepared by dissolving 0.23 mol of benzoic acid and 0.27 mol of sodium benzoate in water sufficient to yield 1 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_a of benzoic acid is 6.3 x 10^-5.

H₃O⁺

benzoic acid

H₂O

benzoate

This is a buffer solution: the pH does not change upon addition of acid or base

The buffer solution with a pH of 4.31 is prepared with 1 M HC₂H₃O₂ (weak acid) and _____ M NaC₂H₃O₂ (strong electrolyte). The K_a of HC₂H₃O₂ is 1.8 x 10^-5.

A solution containing which one of the following pairs of substances will be a buffer solution?

CsF, HF

NaI, HI

RbCl, HCl

KBr, HBr

none of the above

What change will be caused by addition of a small amount of HCl to a solution containing fluoride ions and hydrogen fluoride?

The concentration of fluoride ion will decrease and the concentration of hydrogen fluoride will increase.

The concentrations of fluoride ions and hydronium ions will both increase.

The concentration of hydrogen fluoride will decrease and concentration of fluoride ions will increase.

The concentration of hydronium ions will increase significantly.

The fluoride ions will precipitate out of solution as its acid salt.

Human blood is ______.

slightly basic

neutral

very basic

very acidic

slightly acidic

What is the pH of a buffer solution that is 0.266 M in lactic acid CH₃CH(OH)COOH (weak acid) and 0.111 M in sodium lactate CH₃CH(OH)COONa (strong electrolyte)? The K_a of lactic acid is 1.4 x 10^-4.

What is the pH of a buffer solution that is 0.193 M in chlorous acid HClO₂ (weak acid) and 0.162 M in sodium chlorite NaClO₂ (strong electrolyte)? The K_a of chlorous acid is 1.1 × 10^-2.