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

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.

Assertion: Zone refining method is very useful for producing semiconductors.

Reason: Semiconductors are of high purity.

Assertion: Hydrometallurgy involves dissolving the ore in a suitable reagent followed by precipitation by a more electropositive metal.

Reason: Copper is extracted by hydrometallurgy.

Explain the following:

Vapour phase refining method is used for the purification of Ti.

Which of the following is not tetrahedral in shape?

Which of the following options are correct for \[\ce{[Fe(CN)6]^{3-}}\] complex?

(i) d²sp³ hybridisation

(ii) sp³d² hybridisation

(iii) paramagnetic

(iv) diamagnetic

Magnetic moment of \[\ce{[MnCl4]^{2-}}\] is 5.92 BM. Explain giving reason.

Explain why \[\ce{[Fe(H2O)6]^{3+}}\] has magnetic moment value of 5.92 BM whereas \[\ce{[Fe(CN)6]^{3-}}\] – has a value of only 1.74 BM.

Why do compounds having similar geometry have different magnetic moment?