Science — AI-generated practice question

When copper sulphate crystals are heated strongly, two changes are observed:

1. Change in colour: The blue colour of copper sulphate crystals changes to white, as the crystals lose water of crystallisation (CuSO₄·5H₂O → CuSO₄ + 5H₂O).

1. Change in state: The hydrated crystals (solid with water) become anhydrous copper sulphate, which is a white powder (solid).

This is a thermal decomposition reaction.

Source: Chapter 1, Chemical Reactions and Equations

The question tests knowledge of the effect of heating a hydrated salt. Key points examiners look for:

• Correct colour change: blue → white (not grey or brown — those relate to other substances).
• Reason: loss of water of crystallisation.
• Mentioning it is a decomposition reaction adds value.
• Note: The source passages describe heating of ferrous sulphate in detail; copper sulphate's dehydration on heating is a standard NCERT-linked fact from the same chapter's context. Do not confuse with copper powder heating (which gives black CuO — a different reaction).