Question

Statement 1: A spontaneous reaction is always exothermic.
Statement 2: Exothermic reaction releases energy from the system.
$A.$ Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of statement 1.
$B.$ Both the statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.
$C.$ Statement 1 is correct but Statement 2 is not correct.
$D.$ Statement 1 is not correct but Statement 2 is correct.
$E.$ Both the Statement 1 and Statement 2 are not correct.

Answer 1

Hint – Here we will proceed by using the concept of spontaneous reaction as well as exothermic reaction. By looking at the concept of this question we can find out the correct statement.

Complete answer:
Spontaneous Reaction: A spontaneous reaction is a reaction that favours formation of products at the conditions under which the reaction is occurring. If the spontaneous reaction has a high activation energy that is rarely attained, the rate of the reaction may be low. For example, when ice melts at ${25^\circ }$C it will melt spontaneously. Water will free spontaneously at ${0^\circ }$C
Exothermic reaction: It is that reaction in which there is release of energy from the system to its surroundings. This energy is usually in the form of heat, light and electricity. For example, any combustion reaction, the thermite reaction. It is the opposite of an endothermic reaction.
And, all spontaneous processes are not exothermic, since the Gibbs free energy determines spontaneity not the enthalpy.
Any process is said to be spontaneous if the Gibbs free energy is negative.
To sum up, we can say that a spontaneous process is not always exothermic.
And, exothermic releases energy from the system.
So, we can say that statement 1 is not correct but statement 2 is correct.

So, option D is correct.

Note – Whenever we come up with this type of problem, one must know that all spontaneous processes are not exothermic reactions, because it is not the Gibbs free energy that determines spontaneity, not the enthalpy. This is a very exothermic process. By using this concept, we can easily explain the statement of this question.