Q. Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a
-
(A)
physical change that can be reversed
-
(B)
chemical change that can be reversed
-
(C)
physical change that cannot be reversed
-
(D)
chemical change that cannot be reversed
✅ Correct Answer: (A)
physical change that can be reversed
Q. Galvanisation is a process used to prevent the rusting of which of the following?
-
(A)
Iron
-
(B)
Zinc
-
(C)
Aluminium
-
(D)
Copper
✅ Correct Answer: (A)
Iron
Q. Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
-
(A)
It is more than 7 metres high
-
(B)
It weighs about 6000 kg
-
(C)
It was built more than 1600 years ago
-
(D)
It has not rusted after such a long period
✅ Correct Answer: (D)
It has not rusted after such a long period
Q. Formation of a compound is
-
(A)
Temporary change
-
(B)
Physical change
-
(C)
Chemical change
-
(D)
Reversible change
✅ Correct Answer: (C)
Chemical change
Q. In which type of change a new substance is formed?
-
(A)
In physical change
-
(B)
In chemical change
-
(C)
In both (a) and (b)
-
(D)
None of these
✅ Correct Answer: (C)
In both (a) and (b)
Q. Neutralisation is a
-
(A)
physical change
-
(B)
chemical change
-
(C)
both (a) and (b)
-
(D)
none of these
✅ Correct Answer: (B)
chemical change
Q. When magnesium is burnt, heat and light are produced. The burning of magnesium is a
-
(A)
reversible change
-
(B)
physical change
-
(C)
chemical and exothermic change
-
(D)
chemical and endothermic change
✅ Correct Answer: (C)
chemical and exothermic change
Q. Which among the following is a physical change?
-
(A)
Cutting a log of wood in small pieces
-
(B)
Burning of wood
-
(C)
Ripening of fruit
-
(D)
Cooking of food
✅ Correct Answer: (A)
Cutting a log of wood in small pieces
Q. What is the formula of rust?
-
(A)
Fe2O3
-
(B)
Fe3O4
-
(C)
FeO
-
(D)
None of these
✅ Correct Answer: (A)
Fe2O3
Q. How crystal of pure substances are obtained?
-
(A)
By crystallization
-
(B)
By chromatography
-
(C)
By peptization
-
(D)
By all these methods
✅ Correct Answer: (A)
By crystallization
Q. Which is a method to prevent rust?
-
(A)
Crystallization
-
(B)
Sedimentation
-
(C)
Galvanisation
-
(D)
None of these
✅ Correct Answer: (C)
Galvanisation
Q. A change in which the original substance can be obtained back by change of conditions is called
-
(A)
reversible change
-
(B)
physical change
-
(C)
chemical change
-
(D)
Both (a) and (b)
✅ Correct Answer: (D)
Both (a) and (b)
Q. The process of forming substances in their pure state from their solution is known as
-
(A)
galvanisation
-
(B)
neutralisation
-
(C)
crystallisation
-
(D)
all of these
✅ Correct Answer: (C)
crystallisation
Q. Which of the following is an example of physical change?
-
(A)
A bud turning into a flower
-
(B)
Rusting of iron
-
(C)
Boiling of water
-
(D)
Ripening of a tomato
✅ Correct Answer: (C)
Boiling of water
Q. Rusting can be prevented by
-
(A)
preventing iron from coming in contact with air and moisture by applying greese or paint
-
(B)
deposit a layer of a metal like chromium or zinc on iron
-
(C)
both (a) and (b)
-
(D)
none of these
✅ Correct Answer: (C)
both (a) and (b)
Q. The process of depositing a layer of zinc on iron is called
-
(A)
galvanisation
-
(B)
neutralisation
-
(C)
crystallisation
-
(D)
none of these
✅ Correct Answer: (A)
galvanisation
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