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Showing posts from May, 2011

CHEMICAL REACTION

1. Which of the following is not a physical change? (a) Boiling of water to give water vapour (b) Melting of ice to give water (c) Dissolution of salt in water (d) Combustion of Liquefied Petroleum Gas (LPG) 2. The following reaction is an example of a 4NH 3 (g) + 5O 2 (g) → 4NO(g) + 6H 2 O(g) (i) displacement reaction (ii) combination reaction (iii) redox reaction (iv) neutralisation reaction (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (iii) (d) (iii) and (iv) 3. Which of the following statements about the given reaction are correct? 3Fe(s) + 4H 2 O(g) → Fe 3 O 4 (s) + 4H 2 (g) (i) Iron metal is getting oxidised (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) 4. Which of the following are exothermic processes? (i) Reaction of water with quick lime (ii) Dilution of an acid (iii) Evaporation