Which of the following statement is NOT true?
(1) First law of thermodynamics suggest that energy is conserved in universe
(2) Second law of thermodynamics the universe tends toward maximum disorder
(3) Standard free energy change ( ΔG” ) is the indicator of spontaneity under cellular conditions physiological
(4) The standard free energy change ( ΔG” ) is the free energy change at 25 deg * C 1 atm pressure, and unit activities of reactants and products in dilute aqueous solution at pH 7.
Correct Answer:
(3) Standard free energy change ( ΔG′ ) is the indicator of spontaneity under cellular conditions (physiological).
Explanation:
- Option (1): First law of thermodynamics suggests that energy is conserved in the universe. This is a true statement. The first law states that energy cannot be created or destroyed, only converted from one form to another.
- Option (2): Second law of thermodynamics suggests that the universe tends toward maximum disorder (entropy). This is also a true statement. The second law indicates that the entropy of an isolated system tends to increase over time.
- Option (3): Standard free energy change ( ΔG′ ) is the indicator of spontaneity under cellular conditions (physiological).
This statement is NOT true.
ΔG′ΔG′ refers to the standard free energy change under standard conditions (25°C, 1 atm pressure, and 1 M concentration of reactants and products), not under physiological conditions. The free energy change under physiological conditions is different, and actual cellular conditions must be considered to determine spontaneity in living organisms. - Option (4): The standard free energy change (ΔG′ ) is indeed defined as the free energy change at 25°C, 1 atm pressure, and unit activities of reactants and products (1 M concentration in dilute aqueous solution at pH 7). This statement is true.
Final Answer:
The incorrect statement is:
(3) Standard free energy change ( ΔG′) is the indicator of spontaneity under cellular conditions (physiological).