Question

Define Gibbs free energy illustrate$$\mathrm{\Delta }G$$ for spontaneous reaction and at equilibrium?

Answer 1

Hint:Standard cell potential of both reactions is given. Standard cell potential is represented b$$E{}^{{}^O}$$. Gibbs free energy is the energy that is available to do useful work. Gibbs free energy is represented by$$\mathrm{\Delta }G$$

Complete step by step answer:
Gibbs free energy may be defined At constant pressure and temperature the maximum work done by the system is measured by Gibbs energy.
 The Gibbs free energy change in between products and reactants is equal to the change in Gibbs energy between products and reactants at standard state are related to each other by this equation-
$$\mathrm{\Delta }G=\mathrm{\Delta }{G}^O+RT\ln Q$$
Here Q= reaction quotient
When $$\mathrm{\Delta }{G}^O=0$$then put this value in above equation-
$$-G^O=2.303\log K_C$$
$$\log K_c=0$$
$$K_C=1$$
Hence the value of , when $$\mathrm{\Delta }G=0$$ for a reaction in equilibrium is 1.

Additional information:
Gibbs free energy is the energy that is available to do useful work.
A reaction spontaneously occurs when$$\mathrm{\Delta }G$$ is negative.
A reaction is nonspontaneous when $$\mathrm{\Delta }G$$ is positive.
Gibbs free energy related to entropy by using this formula $$\mathrm{\Delta }G=\mathrm{\Delta }H-\mathrm{\Delta }T\mathrm{\Delta }S$$ in which$$\mathrm{\Delta }H$$ is the change in enthalpy, $$\mathrm{\Delta }T$$ is the change in temperature and $$\mathrm{\Delta }S$$ is the change in entropy.

Note:
$$\mathrm{\Delta }G$$ is negative in spontaneous reaction. It means that the product of the reaction has less free energy than the reactants because they lose some free energy during the reaction. So this type of reaction is called an exothermic reaction.
$$\mathrm{\Delta }G$$Is positive in nonspontaneous reaction it means that the product of the reaction has more free energy than the reactants because they gain some free energy during the reaction. So this type of reaction is called an endothermic reaction.
Gibbs free energy is used to calculate maximum reversible work.