Question

Two different salts are given to the students in the chemistry laboratory, Salim and javed dissolved these salts in water separately When salim dissolved the salt into water in a beaker, the beaker turn hot from the outside. When Javed dissolved the another salt into the water , the beaker turn cold from the outside. both Salim and javed rushed to the teacher and asked about the phenomenon. The teacher replies to them that when we classify the reaction in exothermiic and endothermic reaction we should check the temperature of the beaker. Exothermic reactions are the reactions in which heat is released during the process while endothermic reactions are the reactions in which heat is absorbed during the reaction.

1. The salt given to the Salim should be (a) Sodium chloride (b) Ammonium nitrate (c) Calcium chloride (d) Zinc chloride

2. The salt given to Javed should be (a) Sodium chloride (b) Ammonium nitrate (c) Calcium chloride (d) Zinc chloride

3. Reaction of magnesiun' with air is (a) Exothermic reaction (b) Endothermic reaction (c) Reversible reaction (d) Substitution reaction

4. Which of the following is an exothermic reaction? (a) Electrolysis of water (b) Dissolution of NH, Clin water (c) Burning ofL.PG (d) Decomposition of AgBr in the presence of sunlight​

Answer 1

1- a

2-c

3-a

4-a

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