Chemistry class12

The molality of pure water is

• 55.5

• 50.5

• 18

• 60.5

Low concentration of oxygen in the blood and tissues of people living at high altitude is due to _________

• low temperature

• low atmospheric pressure

• high atmospheric pressure

• both low temperature and high atmospheric pressure

The value of Henry’s constant KH is

• greater for gases with higher solubility.

• greater for gases with lower solubility.

• constant for all gases.

• not related to the solubility of gases.

A solution containing 10 g per dm3 of urea (molar mass 60 g mol-1) is isotonic with 5% solution of non-volatile solute, MBof solute is

• 300 g mol-1

• 350 g mol-1

• 200 g mol-1

• 250 g mol-1

Cone. H2SO4 is 98 % H2SO4 by mass has d = 1.84 g cm-3. Volume of acid required to make one litre of 0.1 M H2SO4 is

• 5.55 mL

• 10 mL

• 20 mL

• 30 mL

Salt bridge completes internal circuit and prevents accumulation of charges.

• True

• False

A first order reaction has specific reaction rate 10-2s-1. How much time it will take for 20g of reactant to reduce to 5g?

• 138.6 s

• 346.5s

• 693.0s

• 238.6s

In the first order reaction the concentration of reactant decreases from 0.6 M to 0.3 M in 30 minutes. The time taken for the concentration to change from 0.1 M to 0.025 M:

• 60 min

• 30 min

• 15 min

• 50 min

Which among the following is a false statement?

• Rate of zero order reaction is independent of initial concentration of reactant.

• Order can be zero

• Molecularity of a reaction may be zero or fraction.

• Slowest step determines rate of a reaction

In a simple cubic, body-centered cubic and face-centered cubic structure, the ratio of the number of atoms present is respectively.

• 8:1:6

• 1:2:4

• 4:2:1

• 4:2:3