Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Chemistry

Wood spirit is known as acetone:

The number of tripeptides formed by 3 different amino acids.

Which amino acids are chiral?

Among the following a chiral amino acid is:

Assertion: Aryl iodides can be prepared by reaction of arenes with iodine in the presence of an oxidising agent.

Reason: Oxidising agent oxidises I₂ into HI.

A unit cell of NaCl has 4 formula units. Its edge length is 0.50 nm. Calculate the density if molar mass of NaCl = 58.5 g/mol.

Match the following:

Which of the following is the best matched options?

In a reaction, catalyst changes:

(i) physically

(ii) qualitatively

(iii) chemically

(iv) quantitatively

Zone refining is based on the principle that ______.

Electrolytic refining is used to purify which of the following metals?

In which of the following method of purification, metal is converted to its volatile compound which is decomposed to give pure metal?

(i) Heating with stream of carbon monoxide.

(ii) Heating with iodine.

(iii) Liquation.

(iv) Distillation.

In the extraction of chlorine from brine:

(i) ∆G^Θ for the overall reaction is negative.

(ii) ∆G^Θ for the overall reaction is positive.

(iii) E^Θ for overall reaction has negative value.

(iv) E^Θ for overall reaction has positive value.

Why is an external emf of more than 2.2 V required for the extraction of \[\ce{Cl2}\] from brine?

Write two basic requirements for refining of a metal by Mond process and by Van Arkel Method.

Which method is used for refining Zr and Ti? Explain with equation.

How are metals used as semiconductors refined? What is the principle of the method used?

Give two requirements for vapour phase refining.

Match the items of Column I with the items of Column II and assign the correct code:

Assertion: Nickel can be purified by Mond process.

Reason: \[\ce{Ni(CO)4}\] is a volatile compound which decomposes at 460 K to give pure Ni.

Assertion: Zirconium can be purificed by Van Arkel method.

Reason: ZrI₄ is volatile and decomposes at 1800 K.