If gas evolves in a reaction but the colour does not change, what is the correct conclusion?
Answer and explanation
Correct answer: Gas evolution can also be a sign of a chemical reaction
Chemical reactions may show different observable signs, and no single sign must appear in every reaction. Evolution of a gas can indicate that a new gaseous substance has formed, even if the colour remains unchanged. Therefore option A is the correct conclusion. Colour change is only one possible indicator, and gas evolution is not automatically a physical change; its cause and the substances involved must be considered.
Frequently asked questions
What is the correct answer to this question?
Gas evolution can also be a sign of a chemical reaction
Why is this the correct answer?
Chemical reactions may show different observable signs, and no single sign must appear in every reaction. Evolution of a gas can indicate that a new gaseous substance has formed, even if the colour remains unchanged. Therefore option A is the correct conclusion. Colour change is only one possible indicator, and gas evolution is not automatically a physical change; its cause and the substances involved must be considered.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
