What is the slope of the straight line for the graph drawn between ln k and 1/T, where k is the rate constant of a reaction at temperature T?

• -E_a/ 2.303R

• -E_a/R

• E_a/R

• R/E_a

Electrons with a kinetic energy of 6.023 × 10⁴ J/mol are evolved from the surface of a metal, when it is exposed to radiation of wavelength of 600 nm. The minimum amount of energy required to remove an electron from the metal atom is

• 2.3125 × 10^-19 J

• 3 × 10^-19 J

• 6.02 × 10^-19 J

• 6.62 × 10^-34 J

For a first order reaction at 27°C, the ratio of time required for 75% completion to 25% completion of reaction is

• 3.0

• 2.303

• 4.8

• 0.477

At T (K), the ratio of kinetic energies of 4g of H₂ (g) and 8 g of O₂ (g) is

• 1 : 4

• 4 : 1

• 2 : 1

• 8 : 1

Which one of the following plots is correct for a first order reaction?

Which one ofthe following statements is correct for the reaction?

CH₃COOC₂H₅(aq) + NaOH(aq) → CH₃COONa (aq) + C₂H₅OH (aq)

• Order is two but molecularity is one

• Order is one but molecularity is two

• Order is one but molecularity is one

• Order is two but molecularity is two

In a first order reaction, the concentration of the reactant decrease from 0.6 M to 0.3 M in 15 min. The time taken for the concentration to change from 0.1 M to 0.025 M in minutes is

• 14

• 12

• 30

• 3

The time required for a first order reaction to complete 90% is 't'. What is the time required to complete 99% of the same reaction?

• 2t

• 3t

• t

• 4t

The half-life of a radioactive element is 30min, one sixteenth of original quantity of element will remain unchanged after

• 1 h

• 16 h

• 4 h

• 2 h

140.

If the amount of radioactive substance is increased three times, the number of atoms disintegrated per unit time would

• be double

• be triple

• remain one third

• not change