If a substance appears to change colour but no other clear sign of a chemical change is observed, what should be done?
Answer and explanation
Correct answer: Further tests should be performed to check for formation of a new substance and other signs such as gas evolution, precipitate formation, or temperature change.
A colour change can indicate a chemical reaction, but it is not sufficient by itself for a definite conclusion. A more reliable conclusion requires checking for evidence such as formation of a new substance, gas evolution, precipitate formation, or a temperature change. Option D is incorrect because a precipitation reaction normally involves formation of an insoluble solid; a colour change alone does not establish precipitation.
Frequently asked questions
What is the correct answer to this question?
Further tests should be performed to check for formation of a new substance and other signs such as gas evolution, precipitate formation, or temperature change.
Why is this the correct answer?
A colour change can indicate a chemical reaction, but it is not sufficient by itself for a definite conclusion. A more reliable conclusion requires checking for evidence such as formation of a new substance, gas evolution, precipitate formation, or a temperature change. Option D is incorrect because a precipitation reaction normally involves formation of an insoluble solid; a colour change alone does not establish precipitation.
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.
