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

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

With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids

What do you understand by the term glycosidic linkage?

Why does NH₃ act as a Lewis base?

What is the two dimensional coordination number of a molecule in square close packed layer?

A compound forms hexagonal close-packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?

A compound is formed by two elements M and N. The element N forms ccp and atoms of M occupy 1/3^rdof tetrahedral voids. What is the formula of the compound?

How many lattice points are there in one unit cell of the following lattice?

Face-centred cubic

A cubic solid is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-centre. What is the formula of the compound? What are the coordination numbers of P and Q?

Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.

Aluminium crystallises in a cubic close-packed structure. Its metallic radius is 125 pm.

1. What is the length of the side of the unit cell?
2. How many unit cells are there in 1.00 cm³ of aluminium?

The cell in which the following reactions occurs: \[\ce{2Fe^{3+}_{( aq)} + 2I^-_{( aq)} -> 2Fe^{2+}_{( aq)} + I2_{(s)}}\] has \[\ce{E^Θ_{cell}}\] = 0.236 V at 298 K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.

What will be the effect of temperature on rate constant?

The rate of the chemical reaction doubles for an increase of 10 K in absolute temperature from 298 K. Calculate E_a.

The activation energy for the reaction \[\ce{2 HI_{(g)} -> H2_{(g)} + I2_{(g)}}\] is 209.5 kJ mol⁻¹ at 581K. Calculate the fraction of molecules of reactants having energy equal to or greater than activation energy?

The rate constant for the decomposition of N₂O₅ at various temperatures is given below:

Draw a graph between ln k and `1/T` and calculate the values of A and E_a. Predict the rate constant at 30º and 50ºC.

The rate constant for the decomposition of hydrocarbons is 2.418 × 10⁻⁵ s⁻¹ at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor?