When a piece of calcium metal is dropped into a beaker of cold water, a vigorous reaction takes place and the metal gradually disappears to form a white suspension.
(i) Write down the equation for the reaction.
(ii) Why does the solution become milky?
(iii) On filtering, a clear solution is obtained. What is the name of the clear solution?

How is heavy water prepared from neutral water?

What is the importance of heavy water with regard to nuclear power generation?
Or
Discuss the importance of heavy water in nuclear reactor.

Knowing the properties of H₂O and D₂O, do you think that D₂O can be used for drinking purposes? 

What is the difference between 'hydrolysis' and 'hydration'?

Why is concenration of hydrogen peroxide difficult?

What precautions are necessary while storing hydrogen peroxide?
Or
Explain why hydrogen peroxide is stored in coloured/plastic bottles.

Explain why hydrogen peroxide cannot be stored for prolonged periods.