Question

A concentrated weak acid is best described as which of the following?

(a) a solution with a high pH
(b) a solution where the concentration of undissociated acid particles is high and relative quantity of hydronium ions is low
(c) a solution where the concentration of undissociated acid particles is low compared to the concentration of hydronium ions.
(d) a solution where the concentration of the hydronium ions is large compared to the concentration of undissociated acid particles

What would best suit as an answer. Im confused because I had originally thought c but c and d seem like the same answer.

Answer 1

If it is a concentrated solution of a weak acid the equilibrium will be on the side of the undissociated acid.
So:
the concentration of the undissociated acid will be high
the concentration of the dissociated acid will be low
the concentration of the dissociated H+ will be low.

a) is wrong as the pH will be low.

b) fits

c) is wrong because the concentration of undissociated acid particles is HIGH compared to the concentration of hydronium ions.

d) is wrong because concentration of the hydronium ions is LOW compared to the concentration of undissociated acid particles .

Answer 2

Thanks :)