CHEMISTRY
WORKSHEET
CHEMICAL REACTIONS & CHEMICAL CHANGES
1 . The reaction between lead nitrate and potassium iodide present in aqueous
solutions is an example of
(a) Decomposition Reaction (b) Displacement Reaction
(c) Double Displacement Reaction (d) Neutralisation
2. Assertion: A lead nitrate on thermal decomposition gives lead oxide, brown
coloured nitrogen dioxide and oxygen gas.
Reason: Lead nitrate reacts with potassium iodide to form yellow ppt of lead
iodide and the reaction is double displacement as well as precipitation
reaction.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.
3. Silver article turns black when kept in the open for a few days due to formation of
(a) H2S (b) AgS (c) AgSO4 (d) Ag2S
4. Reaction of ‘magnesium’ with air is
(A) Exothermic reaction (B) Endothermic reaction
(C) Reversible reaction (D) Substitution reaction
5. The type of chemical reactions take place when electricity is passed through water is
(a) Displacement (b) Combination (c) Decomposition (d) Double displacement
6. 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 surface of iron nails acquire a black coating
(d) the colour of solution changes to green
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7. Which of the given gases can be used for storage of fresh samples of an oil for a long
time?
(A) Carbon dioxide or oxygen (B) Nitrogen or helium
(C) Helium or oxygen (D) Nitrogen or oxygen
8. The other name for quick lime is ,
(A) Calcium hydroxide (B) Calcium oxide (C) Carbon dioxide (D) Sodium oxide
9. Both CO2 and H2 gases are
(A) Heavier than air (B) Colourless (C) Acidic in nature (D) Soluble in water
10. Which of the following are exothermic processes?
(i) Reaction of water with quick lime (ii) Dilution of an acid
(iii) Evaporation of water (iv) Sublimation of camphor (crystals)
(a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (iii) and (iv)
11. What happens when dilute Sulphuric acid is added to Zn granules?
(a) Hydrogen gas and Zinc chloride are produced.
(b) Chlorine gas and Zinc hydroxide are produced.
(c) No reaction takes place.
(d) Zinc salt and water are produced.
12. A teacher gave two test tubes to the students, one containing water and the other
containing sodium hydroxide. She asked them to identify the test tube containing
sodium hydroxide solution. Which one of the following can be used for the
identification?
(a) Blue litmus (b) Red litmus
(c) Sodium carbonate solution (d) Dilute hydrochloric acid
13. Respiration is a _________ type of reaction .
(a) Exothermic (b) Endothermic (c) Reduction (d) Combination
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14. Which of the following is not a characteristic of a chemical change?
i. It is irreversible.
ii. No net energy change is involved.
iii. A new substance is formed.
iv. Involves absorption or liberation of energy.
15. A reaction of a type: AB + CD → AD + CD, involves
i. No chemical change
ii. Decomposition of AB and CD
iii. Exchange of ions of AB and CD
iv. Combination of AB and CD
16. The reaction BaCl 2 (aq) + H2SO4 (aq) → BaSO4 (s) + 2HCl(aq) is
i. Displacement reaction ii. Neutralisation reaction
iii. Decomposition reaction iv. Double displacement reaction
17. Thermal decomposition of sodium carbonate will produce
i. Carbon dioxide ii. Oxygen
iii. Sodium hydroxide iv. No other product
18. Magnesium ribbon is rubbed before burning because it has a coating of
(a) basic magnesium carbonate (b) basic magnesium oxide
(c) basic magnesium sulphide (d) basic magnesium chloride
19. MnO2 + 4HCl → MnCl2 + 2H2O + Cl2
Identify the substance oxidized in the above equation.
(a) MnCl2 (b) HCl (c) MnO2 (d) H2O
20. Which of the following is an endothermic process?
(a) Dilution of sulphuric acid (b) Condensation of water vapours
(c) Sublimation of dry ice (d) Respiration in human beings
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21. Which of the following statements about the given reaction are correct?
3Fe (s) + 4H2O (g) → Fe3O4 (s) + 4H2 (g)
(i) Iron metal is getting oxidized (ii) Water is getting reduced
(iii) Water is acting as reducing agent (iv) Water is acting as oxidising agent
(a) (i), (ii) and (iii) (b) (iii) and (iv)
(c) (i), (ii) and (iv) (d) (ii) and (iv)
22. Oxidation is a process that involves
(a) addition of oxygen (b) addition of hydrogen
(c) removal of oxygen (d) removal of hydrogen
23. The ratio in which hydrogen and oxygen are present in water by volume is
(a) 1:2 (b) 1:1 (c) 2:1 (d) 1:8
24. Which among the following statement(s) is (are) true?
Exposure of silver chloride to sunlight for a long duration turns grey due to
(i) the formation of silver by decomposition of silver chloride
(ii) sublimation of silver chloride
(iii decomposition of chlorine gas from silver chloride
(iv) oxidation of silver chloride
(a) (i) only (b) (i) and (iii) (c) (ii) and (iii) (d) (iv) only
25. Name the products formed when iron filings are heated with dilute hydrochloric
acid
(a) Fe (III) chloride and water (b) Fe (II) chloride and water
(c) Fe (II) chloride and hydrogen gas (d) Fe (III) chloride and hydrogen gas
