Gas evolution from acid-carbonate reactions upon heating

Steps:

• Review table: Identify components in each mixture (solution and solid).
• Check for reactions producing gas, like decomposition or neutralization.
• Note warming accelerates gas-forming reactions, such as effervescence.
• Select mixture where acid reacts with carbonate to release CO2.

Why B is correct:

• Mixture B combines acid solution with carbonate solid, yielding CO2 gas via the reaction: acid + carbonate → salt + water + CO2, enhanced by heat per Le Chatelier's principle.

Why the others are wrong:

• A: Involves soluble salts; no gas-producing reaction occurs.
• C: Base and ammonium salt may release NH3, but not specifically upon warming.
• D: Inert mixture; no chemical reaction generates gas.

Final answer: B