Practice Pakistan's most useful MCQs for competitive exams

The expression for entropy change given by, ΔS = – nR ln (P2/P1), holds good for___________________?

• (A)  Expansion of a real gas
• (B)  Reversible isothermal volume change
• (C)  Heating of an ideal gas
• (D)  Cooling of a real gas

Answer

Submitted By :Ali Uppal

dW and dq are not the exact differential, because q and W are__________________?

• (A)  State functions
• (B)  Path functions
• (C)  Intensive properties
• (D)  Extensive properties

Answer

Submitted By :Ali Uppal

Which of the following is not a unit of the equilibrium constant Kp? (where, Δx = number of moles of products number of moles of reactants) ?

• (A)  (atm)Δx, when Δx is negative
• (B)  (atm)Δx, when Δx is positive
• (C)  Dimensionless, when Δx = 0
• (D)  (atm)Δx2, when Δx > 0

Answer

Submitted By :Ali Uppal

Fugacity of a component in an ideal gas mixture is equal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at constant pressure and temperature ____________ as its mole fraction increases?

• (A)  Decreases
• (B)  Decreases exponentially
• (C)  Increases
• (D)  Remain constant

Answer

Submitted By :Ali Uppal

(∂E/∂T)V is the mathematical expression for____________________?

• (A)  CV
• (B)  Enthalpy change
• (C)  Free energy change
• (D)  None of these

Answer

Submitted By :Ali Uppal

Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor) ?

• (A)  Freon
• (B)  Liquid sulphur dioxide
• (C)  Methyl chloride
• (D)  Ammonia

Answer

Submitted By :Ali Uppal

A/an ____________ system is exemplified by a vessel containing a volatile liquid in contact with its vapor?

• (A)  Isolated
• (B)  Closed
• (C)  Open
• (D)  None of these

Answer

Submitted By :Ali Uppal

In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when_______________?

• (A)  n = y = 1.4
• (B)  n = 0
• (C)  n = 1
• (D)  n = 1.66

Answer

Submitted By :Ali Uppal

Equilibrium constant decreases as the temperature___________________?

• (A)  Increases, for an exothermic reaction
• (B)  Decreases, for an exothermic reaction
• (C)  Increases, for an endothermic reaction
• (D)  None of these

Answer

Submitted By :Ali Uppal

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

Answer

Submitted By :Ali Uppal