Test: Previous Year Questions - Isolation (Level 1)


8 Questions MCQ Test Chemistry Class 12 | Test: Previous Year Questions - Isolation (Level 1)


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This mock test of Test: Previous Year Questions - Isolation (Level 1) for Class 12 helps you for every Class 12 entrance exam. This contains 8 Multiple Choice Questions for Class 12 Test: Previous Year Questions - Isolation (Level 1) (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Previous Year Questions - Isolation (Level 1) quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Previous Year Questions - Isolation (Level 1) exercise for a better result in the exam. You can find other Test: Previous Year Questions - Isolation (Level 1) extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

The metal extracted by leaching with cyanide is :

 [AIEEE-2002]

Solution:

The correct answer is option B
The metal extracted by leaching with a cyanide is silver.
The reactions involved in the process are shown below.
Ag2​S + 4NaCN ⇌ 2Na[Ag(CN)2​] + Na2​S
2Na[Ag(CN)2​]+ Zn → Na2​[Zn(CN)4​] + 2Ag↓

QUESTION: 2

When the sample of Cu with Zn impurity is to be purfied by electrolysis, the appropriate electrodes are :

Cathode Anode

[AIEEE-2002]

Solution:

The correct answer is Option D.
Impure sample is made of the anode and pure copper acts as the cathode.

QUESTION: 3

Aluminium is industrially prepared by -  

[AIEEE-2002]

Solution:

The correct answer is Option D.
The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite, aluminium's chief ore, through the Bayer process) in molten cryolite, and electrolysing the molten salt bath, typically in a purpose-built cell.
 

QUESTION: 4

The substance not likely to contain CaCO3 is –

[AIEEE-2003]

Solution:

The correct answer is option D
A) On heating, gypsum loses water and gives the hemihydrate (CaSO4. 1/2H2O) or the anhydrite. The hemihydrate known as Calcined gypsum/ Plaster of Paris / stucco is an important building material.
B) Seashells are the exoskeletons of mollusks such as snails, clams, oysters and many others. Such shells have three distinct layers and are composed mostly of calcium carbonate(CaCO​3).
C) Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO3​)2​. 
D) A marble statue typically consists of calcium carbonate.
So Calcined gypsum does not have calcium carbonate.

QUESTION: 5

Which one of the following ores is best concentrated by froath-flotation method ?

[AIEEE-2004]

Solution:

The correct answer is Option C.

Galena (PbS)  is best concentrated by a froth-floatation method.
This method is used for the concentration of sulphide ores such as galena (PbS), zinc blende (ZnS) and copper pyrite (CuFeS2).

QUESTION: 6

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

[AIEEE-2005]

Solution:

The correct answer is option D
In Electrolytic refining, the impure metal is made to act as an anode. A strip of the same metal in pure form is used as a cathode. 
They are put in a suitable electrolytic bath containing a soluble salt of the same metal. 
The more basic metal remains in the solution and the less basic ones go to the anode mud.
Copper is refined using an electrolytic method.
Impurities from the blister copper deposit as anode mud which contains antimony, selenium, tellurium, silver, gold, and platinum; recovery of these elements may meet the cost of refining.

QUESTION: 7

Heating mixture of Cu2O and Cu2S will give –

[AIEEE-2005]

Solution:

The correct answer is Option B.

Heating a mixture of Cu2O and Cu2S will give Cu+SO2
 
2Cu2O+Cu2S→6Cu+SO2

This reaction takes place during bessemerization and is an auto reduction process to give copper metal.

QUESTION: 8

Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly ?  

[AIEEE-2008]

Solution:

Metal sulphides are less stable than the corresponding oxides
Explanation: