Description : Gibbs free energy at constant pressure and temperature under equilibrium conditions is (A) ∞ (B) 0 (C) Maximum (D) Minimum
Last Answer : (D) Minimum
Description : In which of the following reactions, standard reaction entropy change (S°) is positive and standard Gibb's energy change (G°) decreases sharply with increasing temperature? (1) 2 2 1 1 1 C graphite O (g) CO (g) 2 2 2 (2) 2 1 C ... CO(g) O (g) CO (g) 2 (4) 2 1 Mg(s) O (g) MgO(s) 2
Last Answer : C graphite O (g) CO(g)
Description : Gibbs-Duhem equation (A) States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure (B) Applies only to binary systems (C) Finds no application in gas-liquid equilibria involved in distillation (D) None of these
Last Answer : (A) States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Description : The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation. (A) Gibbs-Duhem (B) Van Laar (C) Gibbs-Helmholtz (D) Margules
Last Answer : (A) Gibbs-Duhem
Description : Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure. (A) Fugacity (B) Partial pressure (C) Activity co-efficient (D) All (A), (B), and (C)
Last Answer : (D) All (A), (B), and (C)
Description : Variation of equilibrium pressure with temperature for any two phases of a given substances is given by the __________ equation. (A) Gibbs-Duhem (B) Maxwell's (C) Clapeyron (D) None of these
Last Answer : (C) Clapeyron
Description : If the heat of solution of an ideal gas in a liquid is negative, then its solubility at a given partial pressure varies with the temperature as (A) Solubility increases as temperature ... (D) Solubility increases or decreases with temperature depending on the Gibbs free energy change of solution
Last Answer : (B) Solubility increases as temperature decreases
Description : Pick out the correct statement. (A) A catalyst speeds up the forward reaction but slows shown the reverse reaction (B) Addition of catalyst changes the equilibrium constant (C) Pressure changes do not change the equilibrium concentrations (D) The composition of equilibrium is changed by catalyst
Last Answer : (C) Pressure changes do not change the equilibrium concentrations
Description : Pick out the wrong statement. (A) Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition (B) Alumina is added as a promoter to ... Arrhenius plot (D) Presence of inerts affects the equilibrium conversion of reactants in a chemical reaction
Last Answer : (C) Activation energy for a reaction is obtained from the intercept of the Arrhenius plot
Description : Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature. (A) Infinity (B) Minus infinity (C) Zero (D) None of these
Last Answer : (B) Minus infinity
Description : Gibbs free energy of mixing at constant pressure and temperature is always (A) 0 (B) ∞ (C) + ve (D) - ve
Last Answer : (D) - ve
Description : Specific __________ does not change during phase change at constant temperature and pressure. (A) Entropy (B) Gibbs energy (C) Internal energy (D) Enthalpy
Last Answer : (B) Gibbs energy
Description : Chemical reaction rate of a component depends upon the (A) Composition of the component only (B) Temperature of the system (C) Pressure of the system (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : In the gaseous phase ammonia formation reaction (N2 + 3H2 ⇌ 2NH3 ), the value of the equilibrium constant depends on the (A) Total pressure of the system (B) Volume of the reactor (C) Temperature (D) Initial concentration of N2 and H2
Last Answer : (C) Temperature
Description : The equilibrium constant ‘K’ of a chemical reaction depends on (A) Temperature only (B) Pressure only (C) Temperature and pressure (D) Ratio of reactants
Last Answer : (A) Temperature only
Description : Pick out the wrong statement. (A) The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction (B) With ... phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction
Last Answer : (B) With increase in temperature, the equilibrium constant increases for an exothermic reaction
Description : Assertion :- Catalyst change Gibbs free energy of system. Reason :- Catalyst changes preexponential factor of a chemical reaction.
Last Answer : Assertion :- Catalyst change Gibbs free energy of system. Reason :- Catalyst changes preexponential factor ... . If both Assertion & Reason are false.
Description : The Gibbs free energy change of a reaction at `27^(@)C` is -26 Kcal. and its entropy change is -60 Cals/K. `Delta H` for the reaction is :-
Last Answer : The Gibbs free energy change of a reaction at `27^(@)C` is -26 Kcal. and its entropy change is -60 Cals/K. ... Cals. C. 34 K. Cals. D. `-24` K. Cals.
Description : The equilibrium liquid composition compared to the vapor composition in case of Azeotropic mixture is (A) More (B) Less (C) Same (D) Either more or less; depends on the system
Last Answer : (C) Same
Description : When a gas is expanded from high pressure region to low pressure region; temperature change occurs". This phenomenon is related to the (A) Gibbs-Duhem equation (B) Gibbs-Helmholtz equation (C) Third law of thermodynamics (D) Joule-Thomson effect
Last Answer : (D) Joule-Thomson effect
Description : A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is φi yi P = Yi xifi° where, Φ is a vapor fugacity component, Yiis the liquid activity co- ... and liquid composition xi only (D) Temperature, pressure, liquid composition xi and vapour composition yi
Last Answer : (C) Temperature, pressure and liquid composition xi only
Description : Boiling of liquid is accompanied with increase in the (A) Vapor pressure (B) Specific Gibbs free energy (C) Specific entropy (D) All (A), (B) and (C)
Last Answer : (A) Vapor pressure
Description : (∂H/∂T)P is the mathematical expression for (A) CV (B) Entropy change (C) Gibbs free energy (D) None of these
Last Answer : (D) None of these
Description : Specific/molar Gibbs free energy for a pure substance does not change during (A) Sublimation (B) Vaporisation (C) Melting (D) Either (A), (B) or (C)
Last Answer : (D) Either (A), (B) or (C)
Description : The change in Gibbs free energy for vaporisation of a pure substance is (A) Positive (B) Negative (C) Zero (D) May be positive or negative
Last Answer : (C) Zero
Description : Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.). (A) Entropy (B) Internal energy (C) Enthalpy (D) Gibbs free energy
Last Answer : (D) Gibbs free energy
Description : The change in __________ is equal to the reversible work for compression in steady state flow process under isothermal condition. (A) Internal energy (B) Enthalpy (C) Gibbs free energy (D) Helmholtz free energy
Last Answer : (C) Gibbs free energy
Description : _________ does not change during phase transformation processes like sublimation, melting & vaporisation. (A) Entropy (B) Gibbs free energy (C) Internal energy (D) All (A), (B) & (C)
Last Answer : (B) Gibbs free energy
Description : If a reaction has an enthalpy of -54.32 kJ/mol and an entropy of -354.2 J/(K*mol), what is the Gibbs free Energy at 54.3(degrees c)?
Last Answer : DeltaG = DeltaH - TDeltaS dG = -54.32 kJ/mol - (54'32+273)K(-354.2J/molK) NB Thevtemperature is quoted in Kelvin(K) and the Entropy must be converted to kJ by dividing by '1000'/ Hence dG = ... 115.94 kJ/mol dG = (+)61.61 kJ/mol Since dG is positive, the reaction is NOT thermodynamically feasible.
Description : A system is in ______ equilibrium of its chemical composition does not change with time, i.e., no chemical reaction occurs. A. Chemical B. Thermal C. Mechanical D. Phase
Last Answer : Chemical
Description : In a homogeneous solution, the activity co-efficient of a component depends upon the (A) Pressure (B) Composition (C) Temperature (D) All (A), (B) and (C)
Description : The chemical potential of any constituent of an ideal solution depends on the __________ of the solution. (A) Temperature (B) Pressure (C) Composition (D) All (A), (B) and (C)
Description : In a homogeneous solution, the fugacity of a component depends upon the (A) Pressure (B) Composition (C) Temperature (D) All (A), (B) and (C)
Description : Pick out the wrong statement. (A) A catalyst does not alter the final position of equilibrium in a reversible reaction (B) A catalyst initiates a reaction (C) A catalyst is specific in reaction (D) A catalyst remains unchanged in chemical composition at the end the reaction
Last Answer : (B) A catalyst initiates a reaction
Description : Bound moisture is that liquid which exerts an equilibrium vapor pressure __________ that of the pure liquid at the given temperature. (A) Less than (B) More than (C) Equal to (D) Either (A) or (B); depends on the solid
Last Answer : (A) Less than
Description : With the lowering of equilibrium pressure, at a given temperature, the amount of adsorbate on the adsorbent (A) Increases (B) Decreases (C) Remain same (D) Either (A) or (B), depends on the system
Last Answer : (B) Decreases
Description : Equation which relates pressure, volume and temperature of a gas is called the (A) Equation of state (B) Gibbs Duhem equation (C) Ideal gas equation (D) None of these
Last Answer : (A) Equation of state
Description : In Azeotropic mixture, the equilibrium vapour composition is (A) More than liquid composition (B) Less than liquid composition (C) Same as liquid composition (D) Independent of pressure
Last Answer : (C) Same as liquid composition
Description : In any spontaneous process, the __________ free energy decreases. (A) Helmholtz (B) Gibbs (C) Both ‘a’ & ‘b’ (D) Neither 'a' nor 'b'
Last Answer : (C) Both ‘a’ & ‘b’
Description : Gibbs free energy per mole for a pure substance is equal to the (A) Latent heat of vaporisation (B) Chemical potential (C) Molal boiling point (D) Heat capacity
Last Answer : (B) Chemical potential
Description : The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1is the activity co-efficient of component 1, is (A) A . x22 (B) Ax1 (C) Ax2 (D) Ax12
Last Answer : (A) A . x22
Description : Gibbs free energy (G) is represented by, G = H - TS, whereas Helmholtz free energy, (A) is given by, A = E - TS. Which of the following is the Gibbs Helmholtz equation? (A) [∂(G/T)/∂T] = - (H/T2) (B) [∂(A/T)/∂T]V = - E/T2 (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : The free energy change, AG (A) Is directly proportional to the standard free energy change, AG (B) Is equal to zero at equilibrium (C) Can only be calculated when the reactants and products are present at 1mol/1 concentrations (D) Is equal to –RT in keq
Last Answer : B
Description : Higher free energy of activation of a chemical reaction (at a given temperature) implies (A) Slower rate of reaction (B) Higher rate of reaction (C) Higher equilibrium conversion (D) Both (B) and (C)
Last Answer : (A) Slower rate of reaction
Description : The free energy change for a chemical reaction is given by (where, K = equilibrium constant) (A) RT ln K (B) -RT ln K (C) -R ln K (D) T ln K
Last Answer : (B) -RT ln K
Description : The equilibrium constant of chemical reaction __________ in the presence of catalyst. (A) Increases (B) Decreases (C) Remain unaffected (D) Can either increase or decrease (depends on the type of catalyst)
Last Answer : (C) Remain unaffected
Description : With increase in temperature, the thermal conductivity of fresh lubricating oil (A) Increases (B) Decreases (C) Remains unchanged (D) May increase or decrease; depends on its composition
Description : Diffusion co-efficient of a metal in a solid solution depends upon its (A) Composition (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : When liquid and vapour phases of one component system are in equilibrium (at a given temperature and pressure), the molar free energy is (A) More in vapour phase (B) More in liquid phase (C) Same in both the phases (D) Replaced by chemical potential which is more in vapour phase
Last Answer : (C) Same in both the phases
Description : Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The ratio of chemical potential to free energy of a pure substance ... temperature and pressure is (A) 0 (B) 1 (C) ∞ (D) None of these
Last Answer : (B) 1