Tag: chemistry

Quizzes (490) Questions (9892)

Questions Related to chemistry

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

Which of the following is a physical mean for concentration of ore?

  1. Using sodium hydroxide

  2. Using electrolysis

  3. Froth flotation method

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

In many cases, it is possible to separate the metal compound from unwanted rocky material by physical means. A common example of this involves froth flotation. In this method, the unwanted object binds with air and comes on the surface as bubbles.

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore
State the given statement is true or false.
Statement: Mercuric oxide is reduced by thermal decomposition.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Mercury(II) oxide, a red solid, decomposes when heated to produce mercury and oxygen gas. A reaction is also considered to be a decomposition reaction even when one or more of the products are still compounds. A metal carbonate decomposes into a metal oxide and carbon dioxide gas.

$2HgO(s) \overset{\Delta}\longrightarrow 2Hg(l) + O _2(g)$

Hence, the given statement is $true$.
Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

The order of processes involved in the dressing of an ore are :
(i) grinding and crushing           (ii) hand picking                (iii) pulverization

  1. (i), (ii), (iii)

  2. (i), (iii), (ii)

  3. (ii), (iii), (i)

  4. (ii), (i), (iii)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dressing of ore can be carried out by first handpicking followed by crushing and grinding and then pulverization.


Hence, the correct option is $(D)$

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

The process of carrying out the reduction of metal oxides by heating with coke is termed as :

  1. Roasting

  2. Smelting

  3. Zone refining

  4. Ore dressing
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Smelting is the process where heat is applied to ore to extract the base metal, using a reducing agent. So, it is used to carry out reduction of metal oxides to metal by heating with coke.

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

The above process is:

$HgS\xrightarrow{O _2}HgS.HgO$
                         $\downarrow\Delta$
                        $Hg$ 

  1. auto oxidation

  2. self reduction

  3. thermal reduction

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cinnabar ($HgS$), when heated with a current of $O _2$ gets reduced to $Hg$ without the need of any additional reducing agent. The process involved is known as self reduction

Multiple choice chemistry production of metals extraction of metal from concentrated ore basics of metallurgy extraction of metals from ore

In which of the following chemical leaching is used either in the extraction of metal or in the concentration of ore?

  1. Argentite

  2. Bauxite

  3. Alluvial sand containing gold

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

Chemical leaching is used in the extraction of silver from Argentite (Ag2S) using sodium cyanide solution.