Question

An endothermic reaction is one in which:
A.Heat is converted into electricity
B.Heat is absorbed
C.Heat is evolved
D.Heat changes to mechanical word

Answer 1

Hint: At first we will look into what is given in the question. Then we will define the endothermic reaction. We will also write one example of it. Then we will learn about the exothermic reaction which is just opposite of it. Then we will choose the correct option.

Complete Step by step answer: Step1. We are provided with a reaction type called endothermic reaction. We are given four options related to energy. We can understand that endothermic is related to energy involved in the reaction.
Step2. Endothermic reaction is a type of chemical reaction in which the energy is absorbed by the reactants from the surrounding. Due to absorption of the energy the overall temperature of the surroundings drop. It creates a cooling effect. The entropy of the surrounding will be less than zero
Step3. When ammonium chloride is dissolved with water the salt breaks down into the ammonium and chloride ions. It is an endothermic reaction
Reaction is given below.

$N{H_4}Cl(s) + {H_2}O(l) \to N{H_4}Cl(aq) - Heat$

The melting of icd is one of the examples of the endothermic reaction.
Step4. The opposite of endothermic is the exothermic reaction. In this type the energy is released when any reaction takes place. Its entropy is greater than zero.

Hence we can see that energy is absorbed in the endothermic reaction so Option B is correct.

Note: The endothermic reaction has high activation energy. The activation energy is the minimum energy that is required to take the reaction forward. We can even see the endothermic reaction in baking of the bread.