Practice Pakistan's most useful MCQs for competitive exams

The number of atoms of oxygen present in 11.2 litres of ozone (O3) at N.T.P. are__________________?

• (A)  3.01 × 1022
• (B)  6.02 × 1023
• (C)  9.03 × 1024
• (D)  1.20 × 1024

Answer

Submitted By :Ali Uppal

Diffusion is that property by virtue of which a perfume bottle when opened up in a room, makes the whole room fragrant with its smell. If a perfume ‘X’ diffuses twice as fast as another perfume ‘Y’; what is the molecular weight of ‘Y’, if the vapor density of gas ‘X’ is 2? Molecular weight of gas ‘X’ is to be assumed to be 2 ?

• (A)  2
• (B)  4
• (C)  8
• (D)  16

Answer

Submitted By :Ali Uppal

A metal oxide is reduced by heating it in a stream of hydrogen. After complete reduction, it is found that 3.15 gm of the oxide has yielded 1.05 gm of the metal. It may be inferred that the ____________________?

• (A)  Atomic weight of the metal is 4
• (B)  Equivalent weight of the metal is 4
• (C)  Atomic weight of the metal is 2
• (D)  Equivalent weight of the metal is 8

Answer

Submitted By :Ali Uppal

The osmotic pressure of a solution increases, if its _____________ is decreased?

• (A)  Volume
• (B)  Solute concentration
• (C)  Temperature
• (D)  None of these

Answer

Submitted By :Ali Uppal

Which equation is not an equation of state ?

• (A)  PV = RT + B/V + y/V2 + ….
• (B)  (P + a/V2)(V-b) = RT
• (C)  loge (p/p0) = (λ/R) (1/T0 – 1/T)
• (D)  p = [RT/(V – b)] – (a/TV2)

Answer

Submitted By :Ali Uppal

A sample of well water contains 140 gm/m3 Ca2+ ions and 345 gm/m3 Na+ ions. The hardness of the sample of water, expressed in terms of equivalent CaCO3 in gm/m3 is (assuming atomic masses of Ca :40, Na : 23, C : 12, O : 16) ?

• (A)  350
• (B)  485
• (C)  140
• (D)  345

Answer

Submitted By :Ali Uppal

1 kg/cm2 is equal to________________?

• (A)  760 torr
• (B)  1 KPa
• (C)  10 metres of water column
• (D)  1 metre of water column

Answer

Submitted By :Ali Uppal

One kg of saturated steam at 100°C and 1.01325 bar is contained in a rigid walled vessel. It lias a volume of 1.673 m3. It cools to 98°C; the saturation pressure is 0.943 bar ; one kg of water vapour under these conditions has a volume of 1.789 m3. The latent heat of condensation (kJ/kg-1 ) under these conditions is___________________?

• (A)  40732
• (B)  2676
• (C)  2263
• (D)  540

Answer

Submitted By :Ali Uppal

The hydroxyl ion (OH-) concentration in a solution having pH value 3 will be_________________?

• (A)  10-11
• (B)  10-10
• (C)  10-3
• (D)  10-4

Answer

Submitted By :Ali Uppal

For estimation of heat capacity of a solid compound, one can use________________?

• (A)  Clapeyron’s equation
• (B)  Gibb’s equation
• (C)  Kopp’s rule
• (D)  Trouton’s rule

Answer

Submitted By :Ali Uppal