The constituents of baking powder that makes the dough to rise is

Analysis

The question asks for the specific chemical compound present in baking powder that is responsible for the rising of dough during baking.

Concept Explanation

Baking powder is a chemical leavening agent. It consists of a base (usually sodium bicarbonate) and an acid (or an acidic salt). When baking powder is moistened and heated, a chemical reaction occurs between the base and the acid, releasing carbon dioxide ($CO_2$) gas.

The chemical reaction for the decomposition of sodium bicarbonate (baking soda) when heated is:

The bubbles of carbon dioxide gas become trapped in the dough, causing it to expand or "rise," which gives cakes and bread their light, airy texture.

Step-by-Step Solution

1. Evaluate the options: • A. $NaHCO_3$ (Sodium hydrogen carbonate/Sodium bicarbonate): This is the active ingredient in baking powder that releases $CO_2$ upon heating. • B. $NaOH$ (Sodium hydroxide): This is a strong caustic base (caustic soda) and is not used in baking. • C. $Na_2CO_3$ (Sodium carbonate): This is a product of the decomposition of baking soda, but it is not the primary ingredient used to initiate the rising process. • D. $NaCl$ (Sodium chloride): This is common table salt, used for flavor, not for leavening.

2. Conclusion: Sodium hydrogen carbonate ($NaHCO_3$) is the essential constituent that undergoes thermal decomposition to produce the gas necessary for the dough to rise.

Exam Tip

When you see questions about "rising" in baking, always look for carbonates or bicarbonates. Remember that $NaHCO_3$ is "Baking Soda," and when mixed with an acid, it creates the perfect environment for gas production.