Science (English Medium) Class 12 - CBSE Question Bank Solutions for Chemistry

Predict the products of the following reactions :

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

A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90% completion of this reaction.

(log 2 = 0.3010)

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

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)

Write the structures of the main products when acetone (CH₃ − CO − CH₃) reacts with the following reagent :

Zn − Hg/conc. HCl

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

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 \[\ce{E^\circ_{cell}}\] = 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 581 K. Calculate the fraction of molecules of reactants having energy equal to or greater than activation energy?