Question

What are the two factors that determine the spontaneous reaction?

Answer 1

Hint: A reaction is any process in which the starting materials usually called as the reactants are converted to the final products usually called the products. There are two types of reactions on the basis of their occurrence namely, (i) spontaneous reactions, and (ii) non spontaneous reactions. Both the reactions are determined by the physical properties of the thermodynamics.

Complete answer:
Thermodynamics is the branch of chemistry that deals with the flow of heat, its study and the laws used to study and determine them.
A reaction is said to be spontaneous or feasible iff and only iff it has the tendency to take place in nature in a simple manner only. Like evaporation.
A reaction is said to be non spontaneous or non feasible if and only iff it has no tendency to take place in nature in a simple manner only. Like flow of liquids from bottom to top without any mechanical force.
For the determination of the spontaneity of the reaction, out of four laws of thermodynamics two can be use which gives three factors which are as follows: -
In First law, the Enthalpy can be used. When the reaction releases the energy then it is said to be a spontaneous reaction.
In the second law, the Entropy and the Gibbs free energy tells us about the spontaneity of the reaction. The entropy should be positive for the spontaneous reaction. Whereas the gibbs free energy should be negative for the spontaneous reaction.

Note:
There could be several factors that determine the spontaneity of the reaction, three of them are the enthalpy, the entropy and the Gibbs free energy. If a reaction satisfies any one condition then it is said to be a spontaneous reaction with conditions. But if all the conditions are satisfied then the reaction is spontaneous reaction without any pre required condition.