Answer :

Certainly! Let's delve into the type of reaction expected for the sole reactant [tex]\( \text{NaHCO}_3 \)[/tex] (Sodium bicarbonate).

### Step-by-Step Solution:

1. Identify the Reactant:
- The reactant given is [tex]\( \text{NaHCO}_3 \)[/tex], which is sodium bicarbonate.

2. Determine Common Reactions:
- Sodium bicarbonate commonly undergoes a particular type of reaction when subjected to heat.

3. Understanding Decomposition:
- When sodium bicarbonate ([tex]\(\text{NaHCO}_3\)[/tex]) is heated, it breaks down into three different substances: sodium carbonate ([tex]\(\text{Na}_2\text{CO}_3\)[/tex]), carbon dioxide ([tex]\(\text{CO}_2\)[/tex]), and water ([tex]\(\text{H}_2\text{O}\)[/tex]).

4. Writing the Chemical Equation:
- The chemical equation for the decomposition reaction of sodium bicarbonate is:
[tex]\[ 2\text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_2 + \text{H}_2\text{O} \][/tex]
- This equation shows that two molecules of sodium bicarbonate decompose to form one molecule of sodium carbonate, one molecule of carbon dioxide, and one molecule of water.

5. Classify the Reaction:
- This disintegration of a single compound (sodium bicarbonate) into multiple products (sodium carbonate, carbon dioxide, and water) falls under the category of decomposition reactions.

### Conclusion:

The type of reaction for the sole reactant [tex]\( \text{NaHCO}_3 \)[/tex] (sodium bicarbonate) is a decomposition reaction.

This conclusion is reached by recognizing that sodium bicarbonate, when heated, decomposes into sodium carbonate, carbon dioxide, and water, fitting the characteristics of a decomposition reaction.