In a simple school chemistry experiment, when vinegar (acetic acid) and baking soda (sodium bicarbonate) react together, which gas is produced in large amounts and seen as fizzing bubbles?

Introduction / Context:
Vinegar and baking soda experiments are among the first activities that students perform in school chemistry. When these two common household substances are mixed, vigorous fizzing and bubbling are observed. This question checks whether you understand the basic chemistry behind this reaction and can correctly identify the gas that is produced in large quantities during the process.

Given Data / Assumptions:

• Vinegar is an aqueous solution of acetic acid.
• Baking soda is sodium bicarbonate, a carbonate type salt.
• When an acid reacts with a metal carbonate or bicarbonate, a gas is evolved along with a salt and water.
• The visible observation is effervescence or bubbling in the reaction mixture.

Concept / Approach:
The key concept is the general reaction between an acid and a carbonate or bicarbonate. Acids provide hydrogen ions, while carbonates contain carbon dioxide units bound in the anion. When they react, the acid neutralizes the carbonate and carbon dioxide gas is released. In this specific case, acetic acid reacts with sodium bicarbonate to produce sodium acetate, water, and carbon dioxide gas. The gas forms bubbles that cause the characteristic fizzing seen in the experiment.

Step-by-Step Solution:
Step 1: Identify the reactants as acetic acid (from vinegar) and sodium bicarbonate (baking soda). Step 2: Recall the general acid plus carbonate reaction that produces a salt, water, and carbon dioxide gas. Step 3: Write the word equation: acetic acid + sodium bicarbonate → sodium acetate + water + carbon dioxide. Step 4: Recognize that the visible bubbles and foam are due to the evolution of carbon dioxide gas. Step 5: Match this understanding with the options and select carbon dioxide gas as the correct answer.

Verification / Alternative check:
You can verify this by noting that similar fizzing is observed when dilute hydrochloric acid is added to solid marble chips, which are mainly calcium carbonate. In that case, the gas produced is known to be carbon dioxide, confirmed by turning limewater milky. Since vinegar plus baking soda is another example of an acid reacting with a carbonate type compound, the same type of gas is produced. Textbooks and basic chemistry references consistently describe this reaction as a source of carbon dioxide gas, confirming the conclusion.

Why Other Options Are Wrong:
Hydrogen gas is usually produced when acids react with active metals such as zinc or magnesium, not with bicarbonates. Oxygen gas is associated with decomposition of peroxides or other oxidizing agents, not this neutralization reaction. Nitrogen gas does not take part in this reaction and is not generated from acetic acid or bicarbonate. Therefore, none of these other gases matches the well known acid carbonate reaction pattern.

Common Pitfalls:
A common mistake is to guess hydrogen gas whenever bubbling is observed, without considering the specific type of reaction. Another pitfall is to forget that carbonates and bicarbonates are special because they contain carbon dioxide units that can be released as gas. Carefully identifying the reactants and recalling the general reaction between acids and carbonates helps avoid these errors and leads directly to carbon dioxide as the correct gas.

Final Answer:
When vinegar and baking soda react together, the fizzing bubbles are due to the evolution of carbon dioxide gas.