Q2 of 29 Page 73

Write down the changes that will be seen in each instance and explain the reason behind it.

50ml water is added to 50ml solution of copper sulphate.

The changes observed when 50ml water is added to 50ml solution of copper sulphate are:


i. A reversible reaction takes place.
ii. Colour of copper sulphate changes.


iii. Anhydrous copper sulphate changes to hydrated copper sulphate.
Explanation: The changes occur due to the following reaction



The water of crystallization is taking place in the above reaction. Thus, the colour changes from white to blue


More from this chapter

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1

Identify the odd one out and justify.

A. Chloride, nitrate, hydride, ammonium


B. Hydrogen chloride, sodium hydroxide, calcium oxide, ammonia


C. Acetic acid, carbonic acid, hydrochloric acid, nitric acid


D. Ammonium chloride, sodium chloride, potassium nitrate, sodium sulphate


E. Sodium nitrate, sodium carbonate, sodium sulphate, sodium chloride


F. Calcium oxide, magnesium oxide, zinc oxide, sodium oxide.


G. Crystalline blue vitriol, crystalline common salt, crystalline ferrous sulphate, crystalline sodium carbonate.


H. Sodium chloride, potassium hydroxide, acetic acid, sodium acetate.

 2

Write down the changes that will be seen in each instance and explain the reason behind it.

Two drops of the indicator phenolphthalein were added to 10ml solution of sodium hydroxide.

 2

Write down the changes that will be seen in each instance and explain the reason behind it.

Two or three filings of copper were added to 10ml dilute nitric acid and stirred.

 2

Write down the changes that will be seen in each instance and explain the reason behind it.

A litmus paper was dropped into 2ml dilute HCl. Then 2ml concentrated NaOH was added to it and stirred.