Decomposition Reaction

CBSE TEST PAPER-03 CLASS - X (Chemical Reactions and equations) 1. Take about 5 ml of dil. HCl in a test tube and add a few pieces of fine granules to it. Which gas is evolved? (a) Chlorine (b) Hydrogen (c) HCl (d) Nitrogen 2. Dissolving suger is an example of(a) Physical change (b) Chemical change (c) Redox Reaction (d) None of these. 3. Heat is evolved diving (a) Endothermic Reaction (b) Displacement Reaction (c) Combustion Reaction (d) Combination Reaction 4. Which of the following is not a balanced equation? (a) Fe + Cl2 → FeCl3 (b) Mg + CuSO4 → MgSO4 + C4 (c) NaOH + HCl → NaCl + H 2O (d) Zn + S → ZnS 5. 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 Reaction (1) (1) (1) (1) (1)

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6. 7.

Why is a Combustion reaction an oxidation reaction? Identify the type of chemical reaction (i) A + B → C (ii) A + BC → AC + B

(2) (2)

8. 9.

Why cannot a chemical change be normally reversed? Identify the substance oxidized and reduced in the reaction.
CuO ( s ) + Zn( s ) → ZnO ( s ) + Cu ( s )

(2) (2)

10.

When you mix solutions of lead (II) nitrate and potassium iodide, (a) What is the colour of the precipitate formed? Name the compound evolved? (b) Write a balanced chemical reaction? (c) Is this a double displacement reaction?

(3)

11.

Transfer the following into chemical equations and balance them. (1) Hydrogen gas combines with nitrogen to from ammonia. (2) Hydrogen sulphide gas burns in air to give water and sulphurdioxide. (3) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

(3)

12.

Balance the equations (1) HNO3 + Ca (OH ) 2 → Ca ( NO3 ) 2 + H 2O (2) NaCl + AgNO3 → AgCl + NaNO3 (3) BaCl2 + H 2 SO4 → BaSO4 + HCl

(3)

13.

Write three equations for decomposition reaction where energy is supplied in the form of heat, light and electricity?

(3)

14.

With the help of an activity show that iron is more reactive than copper?

(5)

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