Chapter 1.12, Problem 29P

Interpretation Introduction

Interpretation:

The ${\text{K}}_{\text{a}}$ value of hydrogen cyanide $\text{(HCN)}$ is to be determined using its ${\text{pK}}_{\text{a}}$ value.

Concept Introduction:

${\text{K}}_{\text{a}}$ is acidity constant and strength of acid depends on the conjugate base.

The stronger acid has the weakest conjugate base and weaker acid has its stronger conjugate base.

The strength of acids also expresses by ${\text{pK}}_{\text{a}}$ and it is the negative logarithm of acidity constant ${\text{K}}_{\text{a}}$.

The acidity constant ${\text{K}}_{\text{a}}$ is calculated using the formula ${\text{pK}}_{\text{a}}\text{=}-{\text{log}}_{\text{10}}{\text{K}}_{\text{a}}$.