When sodium bicarbonate (NaHCO3, commonly called baking soda) is heated strongly, which compound is formed as the main solid product of the thermal decomposition reaction?

Introduction / Context:
Sodium bicarbonate, also known as baking soda, is a common household chemical used in cooking, cleaning, and fire extinguishers. When heated, it undergoes thermal decomposition, producing a different sodium compound, along with gas products. Understanding this reaction helps explain how baking soda works in baking and in extinguishing small fires, and it is a standard question in basic inorganic chemistry.

Given Data / Assumptions:

• The reactant is sodium bicarbonate, NaHCO3.
• It is heated strongly, causing decomposition.
• The options include sodium carbonate, sodium hydroxide, sodium peroxide, and sodium monoxide.
• We assume no other reagents are present, only heat.

Concept / Approach:
When sodium bicarbonate is heated, it decomposes according to a well known reaction: 2NaHCO3 → Na2CO3 + CO2 + H2O Here, two moles of sodium bicarbonate yield one mole of sodium carbonate (Na2CO3) as the solid residue, with carbon dioxide and water vapour escaping as gases. Sodium hydroxide, sodium peroxide, and sodium monoxide are not formed in this simple thermal decomposition. Sodium carbonate is a common laboratory and industrial chemical known as washing soda (when hydrated), and it often appears as the product of heating sodium bicarbonate.

Step-by-Step Solution:
Step 1: Write the thermal decomposition equation for sodium bicarbonate. 2NaHCO3 (s) → Na2CO3 (s) + CO2 (g) + H2O (g) Step 2: Identify the solid product on the right side. The solid formed is sodium carbonate, Na2CO3. Step 3: Identify the gaseous products. Carbon dioxide (CO2) and water vapour (H2O) are released. Step 4: Match the solid product to the options and select “Sodium Carbonate”.

Verification / Alternative check:
In baking, the production of CO2 from sodium bicarbonate when heated or when reacting with acids causes dough to rise. The remaining sodium carbonate can impart a slightly alkaline taste if not balanced. In fire extinguishers, the same decomposition helps produce CO2 to smother flames. Chemistry textbooks and lab manuals consistently list sodium carbonate as the solid residue when sodium bicarbonate is strongly heated. There is no simple thermal route from NaHCO3 directly to sodium hydroxide, sodium peroxide, or sodium monoxide under these conditions, which confirms that sodium carbonate is the correct product.

Why Other Options Are Wrong:
Option B (Sodium Hydroxide): NaOH is not produced by simple heating of NaHCO3; it usually forms from reactions with water or other processes. Option C (Sodium Peroxide): Na2O2 is an oxidising agent produced by different chemical reactions, not by decomposing sodium bicarbonate. Option D (Sodium Monoxide): Na2O can form by burning sodium metal in oxygen, not by heating sodium bicarbonate.

Common Pitfalls:
Students sometimes confuse sodium bicarbonate (NaHCO3) with sodium carbonate (Na2CO3) and assume they are interchangeable, or they may think that sodium compounds always go towards sodium hydroxide when heated. Another mistake is not balancing the decomposition equation properly, which can obscure the identification of the correct product. To avoid such errors, memorise the key thermal decomposition: sodium bicarbonate yields sodium carbonate plus CO2 and H2O when heated strongly.

Final Answer:
When sodium bicarbonate is heated strongly, the main solid product formed is Sodium Carbonate (Na2CO3).