Question

Presence of water can be detected by

• A. Adding a drop to anhydrous copper sulphate which changes its colour from white to blue
• B. By boiling and testing for the presence of $H_{2}$and $O_{2}$
• C. By seeing its colour and transparency
• D. By checking the production of lather when mixed with soap.

Answer 1

Answer: (A)

Adding a drop to anhydrous copper sulphate which changes its colour from white to blue

Answer 2

: Anhydrous $CuSO_{4}$in white which on reaction with $H_{2}O$forms hydrated $CuSO_{4}$which is blue in colour.

$\underset{(anhydrous,white)}{CuSO_{4}} + 5H_{2}O \rightarrow \underset{(Hydrated.blue)}{CuSO_{4}.5H_{2}O}$