When you mix a bicarbonate or carbonate compound and acid, why are bubbles formed? A. Carbon dioxide gas is being formed.
B. Acid gas is being formed.
C. Sodium bicarbonate is subliming off.
D. The acid solution is boiling off.

A. Carbon dioxide gas is being formed.

Explanation:

Substances combine to form new products in a chemical reaction. A bicarbonate or carbonate compound has the following chemical formula: XHCO3 (bicarbonate) and XCO3 (carbonate), where X is the cation.

When a bicarbonate/carbonate compound such as sodium carbonate is combined with an acid, a salt and a carbonic acid that eventually decomposes into water and CO2 gas is produced. The equation is as follows:

Na2CO3 (aq) + HCl (aq) ---> NaCl (s) + H20 (l)+ CO2 (g)

The formation of bubbles in a reaction involving bicarbonate/carbonate with an acid is characterized by the formation of a CARBON DIOXIDE GAS.

The bubbles formed when carbonates or bicarbonates are mixed with acid owes to the formation of carbon dioxide.

One of the properties of acids is that they react with bicarbonates and carbonates to yield carbon dioxide. If we take for instance, the reaction between calcium carbonate and hydrochloric acid, the reaction occurs as follows; CaCO3(s) + 2HCl(aq) > CaCl2(aq) + CO2(g) + H2O(l)

We can see from the foregoing that, when you mix a bicarbonate or carbonate compound and acid,  bubbles are formed because carbon dioxide gas is being formed.

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