6. GENERAL PRINCIPLES & PROCESSES OF ISOLATION OF ELEMENTS Objective

6. GENERAL PRINCIPLES & PROCESSES OF ISOLATION OF ELEMENTS


1. Removal of the unwanted materials like sand, clays, etc. from the ore is known as ……., …… Or …….

(A) concentration, dressing, benefaction
(B) separation, refining, gangue
(C) magnetic separation, purification, gangue
(D) washing, refining, amalgamation

Answer ⇒ (A)


2. How do we separate two sulphide ores by froth floatation method ?

(A) By using excess of pine oil
(B) By adjusting proportion of oil to water or using depressant
(C) By using some solvent in which one of the sulphides is soluble
(D) By using collectors and froth stabilisers like xanthates

Answer ⇒ (B)


3. Common impurities present in bauxite are

(A) Cuo
(B) Zno
(C) CaO
(D) SiO2

Answer ⇒ (D)


4. Which of the following ores cannot be concentrated by magnetic separation ?

(A) Haematite
(B) Malachite
(C) Magnetite
(D) Siderite

Answer ⇒ (B)


5. Which of the following metals is extracted using a silica lined convertor ?

(A) Mg
(B) Al
(C) Cu
(D) Zn

Answer ⇒ (C)


6. Which of the following metals cannot be obtained by reduction of its metal oxide by aluminium ?

(A) Cr
(B) Mn
(C) Fe
(D) Mg

Answer ⇒ (D)


7. In metallurgical process, aluminium acts as

(A) an oxidising agent
(B) a reducing agent
(C) acidic flux
(D) basic flux

Answer ⇒ (B)


8. In blast furnace iron oxide is reduced by

(A) silica
(B) carbon monoxide
(C) carbon
(D) lime stone

Answer ⇒ (B)


9. In a thermite process ……. is used as reducing agent.

(A) Zn
(B) Al
(C) Mn
(D) Fe

Answer ⇒ (B)


10. Which of the following slags is produced during extraction of iron ?

(A) CaSiO3
(B) FeSiO3
(C) MgSiO3
(D) ZnSiO3

Answer ⇒ (A)


11. Which of the following reactions takes place at higher temperature range (900 K – 1500 K) in blast furnace ?

(A) 3Fe2O3 + CO → CO → 2Fe3O4 + CO2
(B) FeO + CO → Fe + CO2
(C) Fe3O4 + 4CO → 3Fe + 4CO2
(D) Fe2O3 + CO → 2FeO + CO2

Answer ⇒ (B)


12. Which of the following metals cannot be obtained by electrolysis ?

(A) Cr
(B) Na
(C) Ca
(D) Mg

Answer ⇒ (A)


13. In electro-refining of copper, some gold is deposited as

(A) cathode mud
(B) electrolyte
(C) anode mud
(D) cathode

Answer ⇒ (C)


14. Most electropositive metals are obtained from their ores by

(A) autoreduction
(B) smelting with carbon
(C) electrolysis of fused salts
(D) thermal decomposition

Answer ⇒ (C)


15. During the process of electrolytic refining of copper, some metals present as impurity settle as anode mud. These are

(A) Sn and Ag
(B) Pb and Zn
(C) Ag and Au
(D) Fe and Ni

Answer ⇒ (C)


16. A number of elements are available in earth’s crust but most abundant elements are

(A) Al and Fe
(B) Al and Cu
(C) Fe and Cu
(D) Cu and Ag

Answer ⇒ (A)


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

(A) Cu and Zn
(B) Ge and Si
(C) Zr and Ti
(D) Zn and Hg

Answer ⇒ (A)


18. Dolamite mineral contains

(A) Mg
(B) Al
(C) Ca
(D) K

Answer ⇒ (A)


19. Name important ore of aluminium

(A) Bauxite
(B) Cryolite
(C) Croundum
(D) None

Answer ⇒ (A)


20. NaOH is known as

(A) Caustic soda
(B) Washing soda
(C) Caustic Potash
(D) All

Answer ⇒ (A)


21. The formula of blue vitriol is

(A) CuSO4
(B) CuSO4.5H2O
(C) CaSO4.2H2O
(D) None

Answer ⇒ (A)


Class 12th Chemistry Objective Question English

S.N CHEMISTRY OBJECTIVE English Medium
1 SOLID STATE 
2 SOLUTION
3 ELECTROCHEMISTRY
4 CHEMICAL KINETICS
5 SURFACE CHEMISTRY
6 GENERAL PRINCIPLES & PROCESSES OF ISOLATION OF ELEMENTS
7 THE P-BLOCK ELEMENTS
8 THE D- AND f-BLOCK ELEMENTS
9 CO-ORDINATION COMPOUNDS
10 HALOALKANES AND HALOARENES
11 ALCOHOLS, PHENOLS AND ETHERS
12 ALDEHYDES, KETONES AND CARBOXYLIC ACIDS
13 AMINES
14 BIOMOLECULES
15 POLYMERS
16 CHEMISTRY IN EVERYDAY LIFE
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