Practice Pakistan's most useful MCQs for competitive exams

The necessary and sufficient condition for equilibrium between two phases is_________________?

• (A)  The concentration of each component should be same in the two phases
• (B)  The temperature of each phase should be same
• (C)  The pressure should be same in the two phases
• (D)  The chemical potential of each component should be same in the two phases

Answer

Submitted By :Ali Uppal

For an ideal liquid solution, which of the following is unity ?

• (A)  Activity
• (B)  Fugacity
• (C)  Activity co-efficient
• (D)  Fugacity co-efficient

Answer

Submitted By :Ali Uppal

Internal energy is equal to the heat absorbed in case of a/an ______________ process?

• (A)  Constant volume
• (B)  Polytropic
• (C)  Adiabatic
• (D)  Constant pressure

Answer

Submitted By :Ali Uppal

The expression for entropy change, ΔS = n Cp . ln (T2/T1), is valid for the ______________ of a substance?

• (A)  Simultaneous pressure & temperature change
• (B)  Heating
• (C)  Cooling
• (D)  Both

Answer

Submitted By :Ali Uppal

Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is__________________?

• (A)  1
• (B)  2
• (C)  3
• (D)  4

Answer

Submitted By :Ali Uppal

For a real gas, the chemical potential is given by_____________________?

• (A)  RT d ln P
• (B)  RT d ln f
• (C)  R d ln f
• (D)  None of these

Answer

Submitted By :Ali Uppal

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

Answer

Submitted By :Ali Uppal

For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3.Fugacity of water (in kPa) at 9000 kPa will be__________________?

• (A)  6738.9
• (B)  6753.5
• (C)  7058.3
• (D)  9000

Answer

Submitted By :Ali Uppal

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the _________________?

• (A)  Maxwell’s equation
• (B)  Clausius-Clapeyron Equation
• (C)  Van Laar equation
• (D)  Nernst Heat Theorem

Answer

Submitted By :Ali Uppal

Pick out the undesirable property for a good refrigerant ?

• (A)  High thermal conductivity
• (B)  Low freezing point
• (C)  Large latent heat of vaporisation
• (D)  High viscosity

Answer

Submitted By :Ali Uppal