Chapter 16, Problem 91IAE

Interpretation Introduction

(a)

Interpretation:

The formula for the percent ionization of the weak acid needs to be derived using the appropriate assumptions.

$\text{\%ionized = }\frac{100}{1+{10}^{\left(\text{pK-pH}\right)}}$

Concept introduction:

The pH of the solution is used to measure the hydrogen ion’s molar concentration in the solution, and it is the measure of basicity or acidity of a solution. For any solution, if pH is less than 7 then it is acidic. pH equal to 7 is neutral and solution having pH greater than 7 is basic. The hydrogen ion’s concentration is greater than hydroxide ions in an acidic solution.

Interpretation Introduction

(b)

Interpretation:

The percentage ionization of formic acid solution, HCOOH (aq) needs to be determined, having pH of 2.50.

Concept introduction:

As per the Bronsted-Lowry theory of bases and acids, proton acceptors are bases and proton donors are acids. Molecules which can either accept or donate the proton are known as amphiprotic. So, an amphiprotic act as either base or acid. Hydrogen sulfate ion, hydrogen carbonate ion, amino acids and water are common illustrations of amphiprotic molecules because they might donate the proton. Moreover, all of the amphiprotic species have hydrogen atom.

Interpretation Introduction

(c)

Interpretation:

The value of K_a of a 0.150 M solution of propanoic acid with pH 2.85 needs to be determined.

${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CO}}_{\text{2}}\text{H}+{\text{H}}_{\text{2}}\text{O}\to {\text{H}}_{\text{3}}{\text{O}}^{+}+{\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CO}}_2^{-}$

Concept introduction:

As per the Bronsted-Lowry theory of bases and acids, proton acceptors are bases and proton donors are acids. Molecules which can either accept or donate the proton are known as amphiprotic. So, an amphiprotic act as either base or acid. Hydrogen sulfate ion, hydrogen carbonate ion, amino acids and water are common illustrations of amphiprotic molecules because they might donate the proton. Moreover, all of the amphiprotic species have hydrogen atom.