Correct Option
The correct option is Salt, carbon dioxide and water.
Explanation
Acids react with metal carbonates and metal hydrogencarbonates (bicarbonates) to form a corresponding salt, water, and carbon dioxide gas. Since metal carbonates and hydrogencarbonates are basic in nature, this reaction is a specific type of neutralisation where an acid is neutralised to form a salt.
Detailed Analysis
- General Reaction: The standard chemical equation for this process is:
Metal Carbonate/Hydrogencarbonate + Acid → Salt + Carbon Dioxide + Water - Example (Metal Carbonate): When sodium carbonate reacts with dilute hydrochloric acid:
Na2CO3(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + CO2(g) - Example (Metal Hydrogencarbonate): When sodium hydrogencarbonate reacts with dilute hydrochloric acid:
NaHCO3(s) + HCl(aq) → NaCl(aq) + H2O(l) + CO2(g) - Identification of Gas: The carbon dioxide gas evolved during this reaction can be identified by passing it through lime water (calcium hydroxide solution), which turns milky due to the formation of a white precipitate of calcium carbonate.
Analysis of Incorrect Options:
- Salt and water only: Salt and water are the products of a standard neutralisation reaction between an acid and a base (metal oxide or hydroxide), not a carbonate.
- Salt and hydrogen gas only: Salt and hydrogen gas are produced when an acid reacts with a reactive metal (e.g., Zinc + HCl), not a metal carbonate.
- Salt and oxygen gas: Oxygen gas is not evolved in reactions between mineral acids and metal carbonates.
Key Takeaway:
The reaction of acids with metal carbonates or metal hydrogencarbonates invariably produces salt, water, and carbon dioxide. This distinguishes it from acid-metal reactions (which produce hydrogen) and simple acid-base reactions (which produce only salt and water).