PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions

(b) Rate constant ‘k’ of a reaction varies with temperature ‘T’ according to the equation:

`logk=logA-E_a/2.303R(1/T)`

Where E_a is the activation energy. When a graph is plotted for `logk Vs. 1/T` a straight line with a slope of −4250 K is obtained. Calculate ‘E_a’ for the reaction.(R = 8.314 JK⁻¹ mol⁻¹)

Draw the structures of the following molecules: (HPO₃)₃

How would you account for the following:

The chemistry of actinoids is more complicated as compared to lanthanoids.

Give reasons for the following: Butan-1-ol has a higher boiling point than diethyl ether.

Arrange the following:

Aniline, p-nitroaniline, p-methylaniline - in the increasing order of their basic strength

The rate constant of a first order reaction increases from 4 × 10⁻² to 8 × 10⁻² when the temperature changes from 27°C to 37°C. Calculate the energy of activation (Ea). (log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)

The rate constant for the first-order decomposition of H₂O₂ is given by the following equation:

`logk=14.2-(1.0xx10^4)/TK`

Calculate E_a for this reaction and rate constant k if its half-life period be 200 minutes.

(Given: R = 8.314 JK^–1 mol^–1)

Give a reason for the following: 

Actinoids show irregularities in their electronic configurations.

What is the role of t-butyl peroxide in the polymerization of ethene?

Write the mechanism of free radical polymerization of ethene.

How would you account for the following:

Actinoid contraction is greater than lanthanoid contraction.

Give reasons : n-Butyl bromide has higher boiling point than t-butyl bromide.

Write the structures of main products when aniline reacts with the following reagents : HCl

Write the chemical equations involved when aniline is treated with the following reagents: HCI

Give reasons for the following : Phenol is more acidic than ethanol.

Give reasons for the following : Boiling point of ethanol is higher in comparison to methoxymethane.

The rate constant of a first order reaction increases from 2 × 10⁻² to 4 × 10⁻² when the temperature changes from 300 K to 310 K. Calculate the energy of activation (E_a).

(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)

Why do actinoids show a wide range of oxidation states?

Write on similarity between the chemistry of lanthanoids and actinoids.

Which of the following is a natural polymer ? Buna-S, Proteins, PVC