. Read the following and answer any four questions from (i) to (v) A girl met with an accident and his leg fractured. She went to orthopedics doctor for treatment. On examination, the doctor mixed the white power in water and applied to her leg along with the cotton and gauze. After a while, it turned into white, solid, hard mass. He said that it would support her fractured bone in the right position.

(1) After treatment, the doctor repacked
the white powder back into moisture
proof, airtight container. Why?
(a) The fungus growth will occur in open
(b) The powder would react to moisture and
turn into solid mass
(c) The powder with react to sunlight and turn
into solid mass
(d) To prevent the stealing of the powder as it
is very expensive
Ans: (b) The powder would react to moisture
and turn into solid mass

(ii) What is ‘white, solid hard mass’ called
as?
(a) Talcum powder
(b) Paris of Plaster
(c) Plaster of Paris
(d) Copper sulphate
Ans: (c) Plaster of Paris

(iv) The reaction involved in the
formation of white mass is:
(a) Combustion (b) Oxidation (c) Mineralisation
(d) Crystallisation
Ans: (d) Crystallisation
Crystallization is defined as a process by
which a chemical is converted from a liquid
solution into a solid crystalline state