Chemistry · Science General

Metallurgical Processes

1,403 Questions

This section explores key metallurgical processes including ore concentration, pyrometallurgy, and metal refining. It also covers corrosion and the properties of refractory materials. These chemistry questions are relevant for engineering and science entrance tests.

Pyrometallurgy furnacesMetal refining techniquesCorrosion protection methodsOre concentrationAuto reduction process

Metallurgical Processes Questions

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Statement 1: A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metals
Statement 2: The new bonds are weaker.

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both the Statement 1 and Statement 2 are correct, but Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct, but Statement 2 is not correct.

  4. Statement 1 is not correct, but Statement 2 is correct.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Both statement right and statement $2$ are correct Explanation.

Note : [alloy is the mixture of different metals .each metal having different size and structural arrangements. The different sizes of atoms in an alloy make their arrangement less regular than a pure metal. This makes the bonds between the atoms weaker and lower melting point.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Surface chemists design alloys for specific functions in everyday life.
Which of the following does not demonstrate a benefit of using an alloy?

  1. Gold is mixed with copper or silver to make a less expensive form that can be used in jewelry.

  2. Smaller atoms of one metal are incorporated into the structure of larger metal atoms to reduce malleability and improve strength of the structure.

  3. Densities of metals are closely matched to increase desirable properties without increased cost.

  4. The conductivity has been eliminated due to the stronger bonding of the different types of metals.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ans: (B) Smaller atoms of one metal are incorporated into the structure of large metal atom to redue malleability and improve strength of structure.

Note : - Smaller atoms have greater ratios of surface area to volume which means greater ratio of atom boundary to dislocation.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Steel, composed of carbon and iron, is an example of an interstitial alloy.
Which of the following choices represents the best explanation for the fact that steel is harder and stronger than pure iron?

  1. Carbon atoms are more reactive with oxygen than iron atoms. This prevents the steel from forming rust.

  2. Carbon atoms are smaller than iron atoms. Carbon atoms fill the spaces between iron atoms, making the structure more rigid.

  3. Carbon atoms form strong bonds with other carbon atoms. This forms a protective layer on the surface of steel.

  4. Both carbon and iron are good conductors of electricity. This makes steel harder and stronger than pure iron.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ans : (B) Carbon atoms are smaller than iron atoms. Carbon atoms fill the spaces between iron atom, making the structure $\%$ more rigid.
Note : - Steel is interstitial alloy of iron and carbon, due to smaller size of carbon, it easily fit between the metal atoms (iron) and provide Extra bonding to neighbouring atom, which makes alloy harder stronger (rigid).
Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

When items of jewellery made of base metals like copper, iron or nickel are placed in a solution containing a compound of gold, a film of gold is deposited by:

  1. cooling to $5$ degree centigrade

  2. adding acid

  3. heating

  4. passing an electric current
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Electroplating is the process in which a layer of a metal is deposited on metallic or non-metallic electrode by electrolysis in an electrolytic cell.

When items of jewellery made of base metals like copper, iron or nickel are placed in a solution containing a compound of gold, a film of gold is deposited by the process of electroplating which  requires passing an electric current in it.
Hence option D gives the correct answer.

Multiple choice chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

Which of the following is a steel that is resistant to acids?

  1. Nickel alloy steel

  2. Molybdenum steel

  3. Stainless steel

  4. Cobalt alloy steel
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Molybdenum can be obtained from the minerals molybdenite, wulfenite and powellite. It is also obtained as a byproduct during tungsten and copper mining and processing. It has one of the highest melting points of all pure elements; however it is not resistant to acids.Hence, molybdenum steel is also not resistant to acids.

Hence option B is correct answer.

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

Food cans are coated with tin and not with zinc because:

  1. zinc is costlier than tin

  2. zinc has a higher melting point than tin

  3. zinc is more reactive than tin

  4. zinc is less reactive than tin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Food cans are coated with tin and not with zinc because zinc is above the tin in reactivity series means more reactive than tin and can react with food elements preserved in it.  

Multiple choice evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

A solution of copper oxide was prepared by heating, igniting and precipitation. Which of the following method will give higher ratio of copper oxide?

  1. Heating

  2. Precipitation

  3. Ignition

  4. All of the above will give the same ratio
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In a compound the ratio of the atoms or element by mass remains always same irrespective of the source of compound. This means a certain compound always formed by the combination of atoms in same ratio by mass. Hence, copper oxide made from any method will always give the same ratio of copper oxide.

Multiple choice evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

The percentage of copper and oxygen in a sample of CuO obtained from different methods were found to be same. This proves the law of :

  1. Constant proportion

  2. Multiple proportion

  3. Reciprocal proportion

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

The percentage of copper and oxygen in a sample of CuO obtained from different methods were found to be same. This proves the law of Constant proportion as the ratio of Cu:O remains constant

Multiple choice evs let's play with water law of constant proportion - i law of constant proportion law of definite proportions

The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. This illustrates the law of:

  1. Constant proportion

  2. Conservation of mass

  3. Multiple proportion

  4. Reciprocal proportion
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In chemistry, the law of definite proportions, sometimes called Proust's law or the law of definite composition, states that a chemical compound always contains exactly the same proportion of elements by mass and this law further says that, in any particular chemical compound, all samples of that compound will be made up of the same elements in the same proportion or ratio. For example, any water molecule is always made up of two hydrogen atoms and one oxygen atom in a ratio.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Blister copper obtained during extraction from cuprous oxide is called so because:

  1. it has blister like eruptions due to evolution of gas

  2. it has a shining surface like blister

  3. it is the most impure form of copper

  4. its surface is uneven due to different thickness at different place
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The various reaction involved in extraction of copper from cuprous oxide are:
$2FeS+3O _2 \rightarrow 2FeO+2SO _2$
$FeO+SiO _2 \rightarrow FeSiO _3$
$2Cu _2S+3O _2 \rightarrow 2Cu _2O+2SO _2$
$2Cu _2O+Cu _2S \rightarrow 6Cu+SO _2$
The solidified copper obtained has blistered appearance due to the evolution of $SO _2$ and so it is called blister copper.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Why is partial roasting of sulphide ore done in metallurgy of copper?

  1. Auto-reduction of $CuO$ formed is carried out by remaining $CuS$ in the reaction.
  2. $Cu$ is separated out by partial reduction due to sedimentation.
  3. Due to difference in gravity $CuO$ and $CuS$ are separated.

  4. Complete roasting cannot be done in one step hence partial roasting is done.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Partial reduction of Sulphide ores gives copper oxide which further reacts with copper sulphide to show an auto reduction.

$2CuS+3O _2\longrightarrow 2CuO+2SO _2$
$2CuO+CuS\overset {Autoreduction}{\longrightarrow}3Cu+SO _2$

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Blister copper is:

  1. impure copper

  2. obtained in self-reduction process during bessemerisation

  3. both are correct

  4. none is correct
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Blister copper is a form of a impure copper which is obtained in self reduction process during bessemerization.

Reactions take place in blast furnace-
$2Cu _2O+Cu _2S\longrightarrow 6Cu+SO _2$
The molten metal is cooled in sand moulds $SO _2$ escapes. The impure copper metal is known as "Blister copper" and is about $98\%$ pure.

Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

Mark the incorrect statement.

  1. Copper is extracted by smelting in a reverberatory furnace.

  2. Zinc is extracted by reduction of oxide with aluminum.

  3. Aluminium is extracted by electrolysis of its oxide.

  4. Iron is extracted by reduction of its oxide in blast furnace.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
It is not profitable method for extraction of Zinc. Zinc is extracted by distillation and by electrolytic refining. So, it is not extracted by reduction of oxide with Aluminium.
Multiple choice chemistry general principles of metallurgy extraction of copper and zinc extraction of copper and zinc from their oxides basics of metallurgy

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

  1. $Mg$
  2. $Al$
  3. $Cu$
  4. $Zn$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

During the extraction of copper from cuprous oxide $(copper[I]oxide)$ the ore is heated in a reverberatory furnace after mixing with silica. In the furnace, iron oxide, slag of iron silicate and copper is produced in the form of copper matte. This contains $Cu _2S$ and $FeS$.

$FeO+SiO _2\longrightarrow \underbrace {FeSiO _3} _{(slag)}$
Copper matte is then charged into silica lined converter. Some silica is also added and hot air blast is blown to convert the remaining $FeS _2, FeO$ and $Cu _2S/Cu _2O$ to metallic copper.