In addition to sodium hydrogencarbonate, bakings powder contains a substance 'X'. Name the substance 'X'.

Explanation

To solve the question about the substance 'X' found in baking powder, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components of Baking Powder**:
Baking powder is a leavening agent used in cooking, particularly in baking. It typically contains two main components: sodium hydrogen carbonate (also known as sodium bicarbonate) and an acid.

2. **Determine the Acid Present**:
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