Tag: production of metals

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Questions Related to production of metals

Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

Sodium is obtained by the electrolysis of:

  1. an aqueous solution of sodium chloride

  2. an aqueous solution of sodium hydroxide

  3. fused sodium chloride

  4. fused sodium sulphate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sodium is obtained by the electrolysis of fused mixture of $NaCl$ and $CaCl _2$ (Down's process). Reaction can be written as:

$2NaCl \rightarrow 2Na + {Cl} _2$


Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

Which of the following pair can be refined using same basic principle?

  1. $Cu$ and $Ag$
  2. $Si$ and $Ge$
  3. $Ti$ and $Ni$

  4. All of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Copper and Silver are often refined using electrolytic refining, where an impure metal anode is dissolved and pure metal is deposited at the cathode. Silicon and Germanium are typically refined using zone refining.

Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

(a) Mond process       (1) Ni
(b) Van-Arkel              (2) Zr
(c) Liquation               (3) Ga
(d)Zone refining         (4) Sn
Correct option is:

  1. $a-(1)$ $ b-(2)$ $c-(2)$ $d-(4)$
  2. $a-(1)$ $b-(2) $ $c-(4)$ $d-(3)$
  3. $a-(3)$ $b-(2)$ $c-(4)$ $d-(1)$
  4. $a-(2)$ $b-(3)$ $c-(4)$ $d-(1)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Solution:- (B) $a-(1)$ $b-(2) $ $c-(4)$ $d-(3)$
(a) Mond process     $ \Rightarrow$ Ni
(b) Van-Arkel            $ \Rightarrow$ Zr
(c) Liquation             $ \Rightarrow$ Sn
(d)Zone refining       $ \Rightarrow$ Ga
Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

An insoluble substance or mixture that collects at the anode in an electrolytic refining or plating process is known as anode mud.

State True or False.

  1. True

  2. False

  3. Cannot be determined

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Anode mud is the insoluble impurity which settles down at the bottom of the anode during electrolytic refining. The soluble impurities go into the solution.

So the given statement is correct
Hence option $A$ is correct.

Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

Gold is extracted by hydrometallurgical process, based on its property:

  1. of being electropositive

  2. of being less reactive

  3. to form complex which are water soluble

  4. to form salt which are water soluble
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Hydrometallurgy is a method for obtaining metals from their ores. It is a technique within the field of extractive metallurgy involving the use of aqueous chemistry for the recovery of metals from ores, concentrates, and recycled or residual materials. Gold is extracted by hydrometallurgical process, based on its property to form complexes which are water soluble.

$4Au(s)+8CN^- +O _2(g)+2H _2O\rightarrow \underset{soluble \, complex}{4[Au(CN) _2]^-} + 4OH^-$
Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

Which of the following is true for electrolytic refining?

  1. Pure metal is anode and impure metal is cathode

  2. Pure metal is cathode and impure metal is anode

  3. Both are anode

  4. Both are cathode
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
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.
Zinc, copper is refined by this method.
Multiple choice chemistry production of metals refining of metals basics of metallurgy basic metallurgical processes

The method used in metallurgy to refine the impure metal is:

  1. Mond process

  2. Van Arkel process

  3. Liquation

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
$\text{Mond Method:}$ It is specially used for Ni. The vapour phase refining of Ni on heating in a stream of CO forms volatile $Ni(CO) _4$. These vapours when subjected to still higher temperature, decompose to give pure metal.

$\text{Liquation Method:}$ Pb, Sn, Bi, Zn etc are purified by this method. The metal has a low melting point and impurities have a high melting point. In an open hearth, the metal is heated to its melting point and metal melts down and impurities remain behind.

$\text{Van Arkel method}$: This method is used for ultrapure metals like Ti, Zr etc. The metal is converted into its volatile stable compound such as $TiI _4$, leaving behind impurities. The stable volatile compound thus formed is decomposed to get the pure metal.

Hence, option D is correct.