Chapter 12, Problem 8RQ

Interpretation Introduction

Interpretation: It is given that for a common type of reaction the value of $K<<1$. The assumption made when solving the equilibrium concentrations for reactions with small $K$ values and the procedure followed if the ‘ $5\%$ rule’ fails are to be stated.

Concept introduction: If the error in the equilibrium concentration calculated is less than $5\%$, the assumption made is stated to be correct. This is known as the ‘ $5\%$ rule’. If the error exceeds the $5\%$ value, then the quadratic formula is used for calculating the equilibrium concentrations.

To determine: The assumption made when solving the equilibrium concentrations for reactions with small $K$ values and the procedure followed if the ‘ $5\%$ rule’ fails.