Half-life of a reaction is found to be inversely proportional to the cube of initial concentration. The order of reaction is

• 5

• 2

• 4

• 3

A chemical reaction was carried out at 300 K and 280 K. The rate constants were found to be K₁ and K₂ respectively. Then

• K₂ ≈ 0.25 K₁

• K₂ ≈ 0.5 K₁

• K₂ ≈ 4 K₁

• K₂ ≈ 2 K₁

Kinetic theory of gases presumes that collision between the molecules to be perfectly elastic because

• collisions will not split the molecule

• the molecules are tiny

• the molecules are rigid

• the temperature remains constant irrespective of collisions

If E_a = 30 kcal mol^-1 ,what is the effect on rate constant of a reaction for 10°C rise in temperature? It will increase

• three-fold

• two-fold

• three and half-fold

• four-fold

In the case of a radio isotope the value of T_1/2 and λ are identical in magnitude. The value is

• 0.693

• (0.693)^1/2

• 1/ 0.693

• (0.693)²

For gaseous reaction, the following data is given

A → B, k₁ = 10¹⁵ e^-2000/T

C → D, k₂ = 10¹⁴ e^-1000/T

The temperature at which k₁ = k₂ is

• 2000 K

• 868.8 K

• 434.2 K

• 1000 K

197.

The conversion of cis-1, 2-dichloroethene to trans-1, 2-dichloroethene is an example of

• pseudo-unimolecular reaction

• the reaction having order between 1 and 2

• unimolecular reaction

• The conversion is spontaneous so zero-order reaction.

For a reaction A + B → C + D, if concentration of A is doubled without altering that of B, rate doubles. If concentration of B is increased nine times without altering that of A, rate triples. Order of the reaction is

• 2

• 1

• $1\frac{1}{2}$

• $1\frac{1}{3}$

A radioactive isotope decays at such a rate that after 192 minutes only 1/16 of the original amount remains

• 32min

• 48min

• 12min

• 24min

Temperature coefficient of a reaction is 2. When temperature is increased from 30°C to 100°C, rate of the reaction increases by

• 128 times

• 100 times

• 500 times

• 250 times