Practice Pakistan's most useful MCQs for competitive exams

Under conditions of equal reduced pressure and equal reduced temperature, substances are said to be in the ‘corresponding states’. At equal reduced conditions i.e., at the corresponding state, the ____________ of different gases are nearly the same?

• (A)  Compressibility
• (B)  Molecular weight
• (C)  Humidity
• (D)  None of these

Answer

Submitted By :Ali Uppal

At 100°C, water and methylcyclohexane both have vapour pressures of 1 atm. Also at 100°C, the latent heats of vaporisation of these compounds are 40.63 kJ/mole for water and 31.55 kJ/mole for methylcyclohexane. The vapour pressure of water at 150°C is 4.69 atm. At 150°C, the vapour pressure of methylcyclohexane would be expected to be_________________?

• (A)  Significantly less than 4.69 atm
• (B)  Nearly equal to 4.69 atm
• (C)  Significantly more than 4.69 atm
• (D)  Indeterminate due to lack of data

Answer

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The boiling points for pure water and pure toluene are 100°C and 110.6°C respectively. Toluene and water are completely immiscible in each other. A well agitated equimolar mixture of toluene and water are prepared. The temperature at which the above mixture will exert a pressure of one standard atm. is___________________?

• (A)  Less than 100°C
• (B)  100°C
• (C)  Between 100 and 110°C
• (D)  110.6°C

Answer

Submitted By :Ali Uppal

Assume that benzene is insoluble in water. The normal boiling points of benzene and water are 80.1 and 100°C respectively. At a pressure of 1 atm, the boiling point of a mixture of benzene and water is__________________?

• (A)  80.1°C
• (B)  Less than 80.1°C
• (C)  100°C
• (D)  Greater than 80.1°C but less than 100°C

Answer

Submitted By :Ali Uppal

For an ideal gas, the compressibility factor________________?

• (A)  Decreases with pressure rise
• (B)  Is unity at all temperature
• (C)  Is unity at Boyle’s temperature
• (D)  Zero

Answer

Submitted By :Ali Uppal

An Azeotropic solution of two liquids has boiling point lower than either of them, when it_____________?

• (A)  Is saturated
• (B)  Is unsaturated
• (C)  Shows negative deviation from Raoult’s law
• (D)  Shows positive deviation from Raoult’s law

Answer

Submitted By :Ali Uppal

A vapor whose partial pressure is less than its equilibrium vapor pressure is called the _____________ vapor?

• (A)  Saturated
• (B)  Superheated
• (C)  Unsaturated
• (D)  Dry gaseous

Answer

Submitted By :Ali Uppal

Specific gravity on API scale is given by the relation (where, G = specific gravity at 15.5°C) ?

• (A)  °API = 200(G – 1)
• (B)  °API = (141.5/G) – 131.5
• (C)  °API = (140/G) – 130
• (D)  °API = 145 – (145/G)

Answer

Submitted By :Ali Uppal

Internal energy of a substance comprises of the _____________ energy?

• (A)  Vibrational
• (B)  Rotational
• (C)  Translational
• (D)  All

Answer

Submitted By :Ali Uppal

Isotonic solutions must have the same__________________?

• (A)  Viscosity
• (B)  Molar concentration
• (C)  Normality
• (D)  Critical temperature

Answer

Submitted By :Ali Uppal