The Gibbs function (G) in thermodynamics is defined as G = H - TS (Where, H = enthalpy, T = temperature, S = entropy). In an isothermal, isobaric, reversible process, G

CONCEPT:Gibbs Function (G): Gibbs free energy is the thermodynamic potential use to calculate maximum reversible work at constant TEMPERATURE and pressure.It is an extensive property.It is expressed as:G = H – TSWhere, H = enthalpy, T = temperature, S = entropyThe enthalpy (H) of a system is given by:H = E + P VWhere E is the internal energy of the system, P is pressure, and V is VOLUME.​Boyle’s law/Isothermal process: It allows to set up the relationship between the changes in pressure and volume under constant temperature:P1V1 = P2V2 so P V = Constant Where P1 and P2 are the pressure of GASES and V1 and V2 are volumeCharles’s law/Isobaric process: It allows to set up the relationship between the changes in volume and temperature under constant pressure:V1/T1 = V2/T2 so V ∝ T V1 and V2 are volume and T1 and T2 are different temperaturesReversible process: The process in which the system and surroundings can be restored to the initial state from the final state without producing any changes in the thermodynamic properties of the universe is called a reversible process.The ENTROPY (S) of the universe remains constant in a reversible process.The internal energy (E) of a reversible process remains constant.EXPLANATION:Given that:G = H - T SSince H = E + P VSo G = E + P V - T SWe have given, isothermal process (T = constant), isobaric (P = constant), and reversible process (E and S are constant):⇒ G will varies linearly with volume (V).Hence option 2 is correct.