**Category:** Organic Chemistry  
**Subtype:** Combustion Reactions and Stoichiometry  
**Problem Description:** This problem involves a mixture of amino acids and amines that undergo complete combustion, requiring a specific amount of oxygen and producing carbon dioxide, water, and nitrogen. The task is to determine the amount of potassium hydroxide (KOH) that reacts with the mixture after combustion. 

**Key Points:**
- The mixture contains glycine, alanine, valine, methylamine, and ethylamine.
- The combustion of 0.16 mol of the mixture consumes 0.54 mol of O₂ and produces 0.38 mol of CO₂.
- The problem requires calculating the amount of KOH that reacts with the remaining components of the mixture after combustion. 

**Objective:** Find the value of 'a', the number of moles of KOH that participate in the reaction.