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

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

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?

Answer the following question.
Write the products obtained after the hydrolysis of lactose.

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.