Practice Pakistan's most useful MCQs for competitive exams

One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is_________________?

• (A)  30554
• (B)  10373
• (C)  4988.4
• (D)  4364.9

Answer

Submitted By :Ali Uppal

A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is_________________?

• (A)  349
• (B)  651
• (C)  667
• (D)  1000

Answer

Submitted By :Ali Uppal

A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system is______________?

• (A)  3
• (B)  4
• (C)  5
• (D)  6

Answer

Submitted By :Ali Uppal

In Joule-Thomson porous plug experiment, the__________________?

• (A)  Enthalpy does not remain constant
• (B)  Entire apparatus is exposed to surroundings
• (C)  Temperature remains constant
• (D)  None of these

Answer

Submitted By :Ali Uppal

There is a change in ______________ during the phase transition?

• (A)  Volume
• (B)  Pressure
• (C)  Temperature
• (D)  All a, b & c

Answer

Submitted By :Ali Uppal

Cv is given by__________________?

• (A)  (∂E/∂T)V
• (B)  (∂E/∂V)T
• (C)  (∂E/∂P)V
• (D)  (∂V/∂T)P

Answer

Submitted By :Ali Uppal

The equation relating E, P, V and T which is true for all substances under all conditions is given by (∂E/∂V)T = T(∂P/∂T)H – P. This equation is called the ___________________?

• (A)  Maxwell’s equation
• (B)  Thermodynamic equation of state
• (C)  Equation of state
• (D)  Redlich-Kwong equation of state

Answer

Submitted By :Ali Uppal

The standard Gibbs free energy change of a reaction depends on the equilibrium______________________?

• (A)  Pressure
• (B)  Temperature
• (C)  Composition
• (D)  All A,

Answer

Submitted By :Ali Uppal

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 y1 is the activity co-efficient of component 1, is__________________?

• (A)  A . x22
• (B)  Ax1
• (C)  Ax2
• (D)  Ax12

Answer

Submitted By :Ali Uppal

For an isothermal process, the internal energy of a gas____________________?

• (A)  Increases
• (B)  Decreases
• (C)  Remains unchanged
• (D)  Data insufficient, can’t be predicted

Answer

Submitted By :Ali Uppal