Answer :
The % acid dissociation of a 1.20M hydrofluoric acid solution with a pH of 1.55 can be calculated using the hydronium ion concentration derived from the pH and the initial acid concentration. By using the % ionization formula, we can determine the degree of dissociation in percentage form.
The question involves the calculation of the % acid dissociation of a hydrofluoric acid solution based on its pH and given concentration. Hydrofluoric acid (HF) is a weak acid with a pKa of 3.17. The acid dissociation percent can be calculated using the expression % ionization = ([H+]/[HA]) ×100, where [H+] is the concentration of the hydronium ion and [HA] is the initial concentration of the acid.
Given that the pH of the 1.20M solution is 1.55, we can find the concentration of H+ by using the relation pH = -log[H+], which gives us [H+] = 10-pH. Substituting the pH value, we get [H+] = 10-1.55.
Calculating this, we find the hydronium ion concentration and then use the initial acid concentration (1.20M) to calculate the percent dissociation. With the hydronium ion concentration known, the percent dissociation is determined by plugging the values into the % ionization formula and then multiplying by 100 to convert to a percentage.
