SCIENCE DEMO MULTIPLE CHOICE QUESTIONS (MCQ’S)

1.5   MULTIPLE CHOICE QUESTIONS : (MCQ’s)

 1. 10g of hydrogen is burnt in the presence of excess oxygen. The mass of water formed is

a) 90 g
b) 45 g
c) 10 g
d) 18 g

 2. Reddish – brown copper metal forms a black solid on combustion. Which of the following statement is incorrect?

a) Black solid is CuO.
b)  The reaction is a redox reaction.
c) It  is precipitation reaction.
d)  Copper is being oxidized.

 3. The electrolytic decomposition of water gives H2 and O2 in the ratio of

a) 1 : 2 by volume
b) 2  : 1 by volume
c) 8 : 1 by mass
d) 1 :  2 by mass

 4. Which of the following gases can be used for storage of fresh sample of oil for a long time?

a) Carbon dioxide or Oxygen
b) Nitrogen or Helium
c) Helium or Oxygen
d) Nitrogen or Oxygen

5. Both CO2 and H2 gases are

a) Heavier than air
b)  Colourless
c) Acidic in nature
d)  Soluble in water

 6. Chemically rust is

a) Hydrated ferrous oxide
b) Only ferric oxide
c) Hydrated ferric oxide
d) None of these

7.Which of the following reaction is used in the whitewashing of walls?

a) 2Ca +  O2  → 2CaO
b) CaO + H2O → Ca(OH)2 + ∆
c)Ca(OH)2 + CO→ CaCO3 + H2O
d) Ca (OH)2 → CaO + H2O

8. When crystals of lead nitrate are heated strongly in a dry test tube

a) Crystals immediately melt
b) A brown residue is left
c) White fumes appear in the tube
d) A yellow residue is left

9. When carbon dioxide is passed through lime water,

a) Calcium hydroxide is formed
b) White precipitate of CaO is formed
c) Lime water turns milky
d) Colour of lime water disappears

10. On immersing an iron nail in CuSO4 solution for few minutes, you will observe

a) No reaction takes place
b) The colour of solution fades away
c) The iron nails acquire a black coating
d) The colour of solution changes to green

11. The reaction in which two compounds exchange their ions to form two new compounds is called

a) Displacement reaction
b) Combination reaction
c) Double displacement reaction
d) Redox reaction

12. In the reaction CuO + H2 Cu + H2O, the correct statement is

a) CuO is an oxidising agent
b) H2 is getting oxidised
c) The reaction is a displacement reaction
d) All of these

13. Which of the following is not an example of a single displacement reaction?

a) CuO + H2 → H2O + Cu
b) Zn + CuSO4   → ZnSO4 + Cu
c) 4NH3 + 5O2 → 4NO + 6H2O
d) Zn + 2HCI  → H2 + ZnCl2

14. Rancidity can be prevented by

a) Adding antioxidants
 b) Storing food away from light
c) Keeping food in refrigerator
d) All of these

15. In which of the following , heat energy will be evolved

a) Electrolysis of water
b) Dissolution of NH4 Cl in water
c) Burning of P.G.
d) Decomposition of AgBr in the presence of sunlight

16.  ____ ores are thermally decomposed to give metal oxide which on reduction give metal.

a) Carbonate
b) Sulphide
c) Bauxite
d)Metallic


17.Rancidity can be prevented by adding ____ to foods containing fat and oil.

a) Salt
b)Preservatives
c) Antioxidants
d) None of these

18.  The process in which taste and smell of food containing oils or fats gets spoiled is called ____.

a) Corrosion
b) Spoilage
c) Turbidity
d) Rancidity

19.  The colour of ferrous sulphate is pale ____ .

a) Blue
b) Green
c) Yellow
d) Pink

20.  Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of ____ .

a) Barium oxide
b)Barium carbonate
c) Barium sulphide
d) Barium sulphate

21.  The reaction in which two compounds exchange their icons and the product formed is insoluble in  water is called ____ reaction .

a) Precipitation
b) Decomposition
c) Thermite
d) None of these

22.  2Cu(s) + O2(g) → ____ .

a) 3CuO(s)
b) CuO(s)
c) 2CuO(s)
d) 4CuO(s)

23.  ____ is used as reducing agent to obtain manganese from Manganese dioxide .

a) Carbon
b) Coke
c) None of these
d) Both of these

24.  In black and white photography ____ gets decomposed due to light and forms Silver metal and Bromine gas.

a) AgCl
b) AgCr
c) AgBr
d) AgO

25.  The reaction representing a chemical change is called a ____ reaction.

a)  Thermite
b) Balanced
c) Skeletal
d) Chemical

26.  The reaction in which more reactive metal displaces the less reactive metal is called ____ reaction .

a) Balanced
b) Skeletal
c) Displacement
d) Decomposition

27.  ____ is a reaction in which energy is required to form glucose from Carbon dioxide and water.

a) Photosynthesis
b) Decomposition
c) Electrolysis
d) None of these

28.  The black coating of copper oxide can be removed chemically by passing ____ gas over heated copper oxide.

a) Hydrogen
b) Nitrogen
c) Hydrogen
d) Carbon di oxide

29.  The reaction in which oxygen is added / hydrogen is removed is called ____ reaction.

a) Skeletal
b) Reduction
c) Decomposition
d) Oxidation

30.  AgNO3 (aq) + NaCl(aq) → AgCl(s) + ____ .

a) NaNO3
b) 2 NaNO3
c) 3 NaNO3
d) 4NaNO3

31.  2FeSO4(s) → Fe2O4(s) + SO4(g) + _____.

a)SO
b) SO
c) 2Fe
d) 3Fe

32.  2AgBr → _____. This reaction is used in photography.

a) 2Ag
b) Br2
 c) 2Ag + Br2
 d) Ag + Br

33.  Cu(s) +2AgNO3 (aq) → Cu(NO3)2 (aq) + _____.

a) Cu
b)2Ag(s)
c) Ag
d) 2Cu

Ans:

1. a)
2. c)
3. b)
4. b)
5. b)
6. c)
7. c)
8. b)
9. c)
10. d)
11. c)
12. d)
13. c)
14. d)
15. c)
16. a)
17. c)
18. d)
19. b)
20. d)
21. a)
22. c)
23. b)
24. c)
25. d)
26. c)
27. a)
28. a)
29. d)
30. a)
31. a)
32. c)
33. b)