In an acidic solution, zinc first releases a gas and then limestone releases another gas. What is the correct identification of both gases?
Answer and explanation
Correct answer: Hydrogen from zinc and carbon dioxide from limestone
The governing concept is recognising characteristic acid reactions. Zinc, a reactive metal, reacts with a dilute acid to form a salt and hydrogen gas, for example Zn + 2HCl → ZnCl2 + H2. Limestone is mainly calcium carbonate; with acid it produces a salt, water, and carbon dioxide, for example CaCO3 + 2HCl → CaCl2 + H2O + CO2. Thus option A correctly identifies the gases. The reversed pair and chlorine or oxygen alternatives do not fit these reactions.
Frequently asked questions
What is the correct answer to this question?
Hydrogen from zinc and carbon dioxide from limestone
Why is this the correct answer?
The governing concept is recognising characteristic acid reactions. Zinc, a reactive metal, reacts with a dilute acid to form a salt and hydrogen gas, for example Zn + 2HCl → ZnCl2 + H2. Limestone is mainly calcium carbonate; with acid it produces a salt, water, and carbon dioxide, for example CaCO3 + 2HCl → CaCl2 + H2O + CO2. Thus option A correctly identifies the gases. The reversed pair and chlorine or oxygen alternatives do not fit these reactions.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
