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General Principles and Processes of Isolation of Elements VVI Questions |Chemistry VVI Questions Class 12th | Chemistry Important Question Bihar Board | Bihar Board Chemistry Class 12th

General Principles and Processes of Isolation of Elements VVI Questions


General Principles and Processes of Isolation of Elements Subjective Questions

Q.1. Silver is a good conductor of electricity. Why ?

Ans – Silver is the best conductor of electricity because it contains a high number of free electron. Silver is expensive metal, due to this reason at place of silver, copper metal is used.


Q.2. What are the advantages of using Cryolite in the electrolytic reduction of alumina ?

Ans – Melting point of alumina is extremely high (2050° C). Addition of cryolite decreases the melting point as well as it increases the conductivity.


Q.3. What is the impurity present in ore called ?

Ans – The undesired material (impurity) present with the ore known as gangue (matrix).


Q.4. What are the differences between Roasting and Calcination ?

Ans – Roasting : The process of heating of metal ore below its melting point in the presence of air is called Roasting. In roasting, ore is converted to  oxide. Mostly sulphide ore are converted to oxide by roasting.

Calcination : The process of heating of metal ore in the absence of air is called Calcination. In calcination, ore is converted to oxide.


Q.5. Define the following 

(a) Roasting 

(b) Smelting

Ans – 

(a) Roasting : Roasting is a process of metallurgy in which a sulphide ore is heated in air. The process may convert a metal sulphide to a metal oxide or to a free metal. Example : Roasting ZnS may yield ZnO

(b) Smelting : Smelting is the process of reduction of the metal oxide by means of mixing carbon in it and heating it at very high temperature.”


General Principles and Processes of Isolation of Elements Objective Questions

“Q.1. Chief ore of Iron is –

(a) Magnetite

(b) Siderite

(c) Haematite

(d) All

Ans -(c) Haematite


Q.2. Copper metal is purified by which of the following method –

(a) Electrolytic refining

(b) Zone refining

(c) Chromatography

(d) None

Ans -(a) Electrolytic refining


Q.3. At process of heating ore of a metal in excess of air below its melting point is called – 

(a) Roasting

(b) Smelting

(c) Calcination

(d) All

Ans – (a) Roasting


Q.4. Sulphide ores are generally concentrated by –

(a) Froth Floatation method

(b) Roasting

(c) Gravity

(d) Reduction by carbon

Ans – (a) Froth Floatation method


Q.5. Cinnabar is – 

(a) HgS

(b) PbS

(c) ZnS

(d) H2S

Ans -(a) HgS


Q.6. Malachite is an ore of –

(a) Iron

(b) Copper

(c) Zinc

(d) Silver

Ans – (b) Copper


Q.7. Concentration of Sulphide ore is done by – 

(a) Froth floatation process

(b) Electrolysis

(c) Roasting

(d) None of these

Ans -(a) Froth floatation process


Q.8. Ore of aluminium is – 

(a) Bauxite

(b) Haematite

(c) Dolomite

(d) None of these

Ans – (a) Bauxite


Q.9. Which one of the following elements is found in free state in nature ?

(a) Sodium

(b) Iron

(c) Zinc

(d) Gold

Ans – (d) Gold


Q.10. Which of the following metals is most abundant in the earth crust ?

(a) Mg

(b) Na

(c) Al

(d) Fe

Ans – (c) Al


Q.11. Smelting involves reduction of metal oxide with – 

(a) Al 

(b) C

(c) Mg

(d) Co

Ans – (b) C


Q.12. The impurity prsesnt in mineral is called –

(a) Flux

(b)  Gangue

(c) Slag

(d) Alloy

Ans – (b) Gangue”


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