Q4 of 44 Page 1

Which of the following are exothermic processes?

1. Reaction of water with quick time


2. Dilution of an acid


3. Evaporation of water


4. Sublimation of camphor (crystals)

When quick lime reacts with water, calcium hydroxide is produced and a large amount of heat is released. Similarly, when an acid or a base is diluted with water, heat is released making it a highly exothermic reaction.


Note: Exothermic processes release energy in the form of heat along with the formation of products. Such processes are hot because they give out heat.

More from this chapter

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2

The following reaction is an example of a

4NH3 (g) +5O2 (g) → 4NO (g) +6H2O (g)


1. displacement reaction


2. combination reaction


3. redox reaction


4. neutralisation reaction

 3

Which of the following statements about the given reaction is correct?

3Fe(s) + 4H2O→ Fe3O4 + 4H2


a. Iron metal is getting oxidised.


b. Water is getting reduced.


c. Water is acting as reducing agent.


d. Water is acting as oxidising agent.

 5

Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of Na0H, anhydrous CuSO2 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement (s) is (are) correct?

1. In beakers A and B, exothermic process has occurred.


2. In breakers A and B, endothermic process has occurred.


3. In breaker C, exothermic process has occurred.


4. In beaker C, endothermic process has occurred.

 6

A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?