CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 6 – general Principles and Processes of Isolation of Elements

0
37

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 6 –  general Principles and Processes of Isolation of Elements

Every year CBSE conducts board exams for 12th standard. These exams are very competitive to all the students. So our website provides online tests for all the 12th subjects. These tests are also very effective and useful for those who preparing for competitive exams like NEET, JEE, CA etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE Class 12 syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 6 – Ggeneral Principles and Processes of Isolation of Elements

Question 1.
The oil used as frothing agent in froth floatation process is
(a) coconut oil
(b) castor oil
(c) palmitic oil
(d) pine oil

Answer

Answer: (d) pine oil


Question 2.
Which of the following metals is not extracted by leaching?
(a) Aluminium
(b) Mercury
(c) Silver
(d) Gold

Answer

Answer: (b) Mercury


Question 3.
Sulphide ore of zinc/copper is concentrated by
(a) floatation process
(b) electromagnetic process
(c) gravity separation
(d) distillation

Answer

Answer: (a) floatation process


Question 4.
Concentration of sulphide ore is done by
(a) froth flotation process
(b) electrolysis
(c) roasting
(d) None of these

Answer

Answer: (a) froth flotation process


Question 5.
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

Answer: (b) By adjusting proportion of oil to water or using depressant.


Question 6.
Which of the following ores is concentrated by chemical leaching method?
(a) Cinnabar
(b) Argentite
(c) Copper pyrites
(d) Galena

Answer

Answer: (b) Argentite


Question 7.
Common impurities present in bauxite are
(a) CuO
(b) ZnO
(c) CaO
(d) SiO2

Answer

Answer: (d) SiO2


Question 8.
Which of the following ores cannot be concentrated by magnetic separation?
(a) Haematite
(b) Malachite
(c) Magnetite
(d) Siderite

Answer

Answer: (b) Malachite


Question 9.
The significance of leaching in the extraction of aluminium is
(a) it helps removing the impurities like SiO2, Fe2O3 etc. from the bauxite ore
(b) it converts the ore into oxide
(c) it reduces melting point of the ore
(d) it eliminates water from bauxite

Answer

Answer: (a) it helps removing the impurities like SiO2, Fe2O3 etc. from the bauxite ore


Question 10.
Which of the following sulphides when heated strongly in air gives the corresponding metal without undergoing separate reduction of oxide?
(a) Cu2S
(b) FeS
(c) HgS
(d) ZnS

Answer

Answer: (c) HgS


Question 11.
An ore of tin containing FeCrO4 is concentrated by
(a) gravity separation
(b) magnetic separation
(c) froth floatation
(d) leaching

Answer

Answer: (b) magnetic separation


Question 12.
Heating pyrites to remove sulphur is called
(a) smelting
(b) calcination
(c) liquation
(d) roasting

Answer

Answer: (d) roasting


Question 13.
Impurities of sulphur, silicon and phosphorus can be removed from cast iron by adding
(a) carbon which reduces the impurities
(b) water which dissolves the impurities
(c) limestone which changes impurities into oxides and pass into slag
(d) iron oxide which reacts with impurities by forming slag

Answer

Answer: (c) limestone which changes impurities into oxides and pass into slag


Question 14.
Which of the following metals is extracted using a silica lined convertor?
(a) Mg
(b) Al
(c) Cu
(d) Zn

Answer

Answer: (c) Cu


Question 15.
In metallurgical process, aluminium acts as
(a) an oxidising agent
(b) a reducing agent
(c) acidic flux
(d) basic flux

Answer

Answer: (b) a reducing agent


Question 16.
Malachite is an ore of
(a) iron
(b) copper
(c) zinc
(d) Sliver




Answer

Answer: (b) copper


Question 17.
Ellingham diagram represents change of
(a) ΔG with temperature
(b) ΔH with temperature
(c) ΔG with pressure
(d) (ΔG – TΔS) with temperature

Answer

Answer: (a) ΔG with temperature


Question 18.
Which of the following metals cannot be obtained by reduction of its metal oxide bv aluminium ?
(a) Cr
(b) Mn
(c) Fe
(d) Mg

Answer

Answer: (d) Mg


Question 19.
For which of the following ores froth floatation method is used for concentration?
(a) Haematite
(b) Zinc blende
(c) Magnetite
(d) Camallite

Answer

Answer: (b) Zinc blende


Question 20.
During the extraction of haematite, limestone is added which acts as
(a) flux
(b) slag
(c) reducing agent
(d) gangue

Answer

Answer: (a) flux


Question 21.
In blast furnace iron oxide is reduced by
(a) silica
(b) carbon monoxide
(c) carbon
(d) lime stone

Answer

Answer: (b) carbon monoxide


Question 22.
Which of the following oxides cannot be reduced by hydrogen?
(a) Ferric oxide
(b) Aluminium oxide
(c) Zinc oxide
(d) Cupric oxide

Answer

Answer: (b) Aluminium oxide


Question 23.
From the Ellingham graph between Gibb’s energy and temperature, out of C and CO with is a better reducing agent for ZnO?
(a) Carbon
(b) CO
(c) Both of these
(d) None of these

Answer

Answer: (a) Carbon


Question 24.
Formula of copper pyrite is
(a)Cu2S
(b) CuFeS
(c) CuFeS2
(d) Cu2Fe2S2

Answer

Answer: (c) CuFeS2


Question 25.
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

Answer: (a) concentration, dressing, benefaction


Question 26.
Ore of aluminium is
(a) bauxite
(b) hematite
(c) dolomite
(d) None of these

Answer

Answer: (a) bauxite


Question 27.
In a thermite process is used as reducing agent.
(a) Zn
(b) Al
(c) Mn
(d) Fe

Answer

Answer: (b) Al


Question 28.
Blister copper is
(a) impure copper
(b) obtained in self reduction process during bessermerisation
(c) Both are correct
(d) None is correct

Answer

Answer: (c) Both are correct


Question 29.
Which of the following slags is produced during extraction of iron?
(a) CaSiO3
(b) FeSiO3
(c) MgSiO3
(d) ZnSiO3

Answer

Answer: (a) CaSiO3


Question 30.
The powdered ore is agitated with water or washed with running stream of water. The heavy ore particles and lighter impurities are separated. This method of concentration is known as
(a) metallurgy
(b) leaching
(c) froth floatation process
(d) gravity separation

Answer

Answer: (d) gravity separation


 

LEAVE A REPLY

Please enter your comment!
Please enter your name here