Tag: non-metals

Questions Related to non-metals

 Copper is extracted from sulphide ore using the method:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Carbon reduction

  2. Carbon monoxide reduction

  3. Auto reduction

  4. None of these

Show answer
Correct Option: C
Explanation:
The copper can be extracted from its sulphide ore by the auto reduction process.
The ore is reduced by heat alone.
 
$Cu _2S + O _2 \rightarrow 2Cu + SO _2$

The copper and the oxygen have been reduced (decrease in oxidation state). The sulphur has been oxidised (increase in oxidation state). The reducing agent is the sulphide ion in the copper(I) sulphide.

Hence, the correct option is $C$

 Which one of the following is not an ore of aluminum?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Bauxite

  2. Corundum

  3. Epsomite

  4. Cryolite

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Correct Option: C
Explanation:

The chief ore of aluminium is bauxite $(Al _2O _3.2H _2O)$. Corundum $(Al _2O _3)$ and Cryolite $(Na _3AlF _6)$ are also aluminium ores. Epsomite is a hydrous magnesium sulfate ore with formula $MgSO _4·7H _2O$.

Which of the following are sulphate ores?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Cinnabar

  2. Gypsum

  3. Galena

  4. Iron pyrite

Show answer
Correct Option: B
Explanation:

Sulphate ores are  Gypsum $(CaSO _4.2H _2O)$, Epsom Salt $(MgSO _4.7H _2O)$, Barytes $(BaSO _4)$ and Anglesite $(PbSO _4)$.

Cinnabar is a mercury sulfide mineral with a chemical composition of $HgS$.
Galena is the natural mineral form of lead(II) sulfide $(PbS)$.
Iron pyrite,  is an iron sulfide with the chemical formula $(FeS _2)$. 

 An alloy which does not contain copper is:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Bronze

  2. Magnalium

  3. Brass

  4. Bell metal

Show answer
Correct Option: B
Explanation:
Bronze: $Cu+ Sn + Al$
Magnalium: $Al + Mg + Ni$ 
Brass: $Cu + Zn$
Bell metal: $Cu + Sn$ 

Hence, the correct option is $B$

 In the extraction of copper from copper pyrites, iron is removed as:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. $FeSO _4$

  2. $FeSiO _3$

  3. $Fe3O _4$

  4. $Fe _2O _3$

Show answer
Correct Option: B
Explanation:
The copper ($II$) ions in the copper pyrite are reduced to copper ($I$) sulphide (which is reduced further to copper metal in the final stage).
The iron in the copper pyrite ends up converted into an iron ($II$) silicate slag which is removed.
$CuFeS _2 + SiO _2 + 4O _2 \rightarrow Cu _2S + 2FeSiO _3 + 3SO _2$

Which of the following combination are correct?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Fluorspar, $FeCO _3$

  2. Zinc blende, $ZnO$

  3. Magnesite, Oxide ore

  4. Cryolite, Halide ore

Show answer
Correct Option: D
Explanation:
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, $CaF _2$. 
Zinc sulfide $(ZnS)$ is a unique compound that forms two types of crystalline structures. These two polymorphs are wurtzite and zincblende.
 
Magnesite is a mineral with the chemical formula $MgCO _3$ (magnesium carbonate).
Cryolite $(Na _3AlF _6)$, sodium hexafluoroaluminate is a halide ore.

Hence, option $D$ is correct.

Which of the following are found as sulphide ores?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. $Al,\ Hg,\ Pb,\ F$

  2. $Fe,\ Zn,\ Pb$

  3. $Hg,\ Pb,\ Na$

  4. $F,\ Ca,\ Cu,\ Mg$

Show answer
Correct Option: B
Explanation:
The sulfide minerals are a class of minerals containing sulfide $(S^{2−})$ as the major anion. Some sulfide minerals are economically important as metal ores. So the metal ion with this anion should have oxidation state $+2$. 
$Fe, Zn, Pb$ all three are found as  sulfide ores. Ores of these metals are known as:  Pyrite $(FeS _2)$, Sphalerite $(ZnS)$ and Galena $(PbS)$ .

 Silica is added to roasted copper ore during extraction in order to remove:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. cuprous sulphide

  2. ferrous oxide

  3. ferrous sulphide

  4. cuprous oxide

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Correct Option: B
Explanation:
Silica is added during smelting in order to remove iron oxides from copper sulphide and oxides. During roasting the iron sulfides react with oxygen (in air or oxygen enriched air) to produce iron oxides (mainly as $FeO$, but with some magnetite $(Fe _3O _4))$ and sulfur dioxide. 
Copper sulfide and iron oxide can mix, but when sufficient silica is added, a separate slag layer is formed. 
The slag forming reaction is:
$FeO + SiO _2 \rightarrow FeO.SiO _2$
Slag is less dense than matte, so it forms a layer that floats on top of the matte.

 Cinnabar is the ore of:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. $Zn$

  2. $Cd$

  3. $Hg$

  4. $Ag$

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Correct Option: C
Explanation:

Cinnabar is the most common  and is the chief ore of mercury with formula $HgS$.

Which of the following is used for decorating sweets?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Copper foil

  2. Aluminium foil

  3. Silver foil

  4. All of these

Show answer
Correct Option: C
Explanation:

Silver foil is used for decorating sweets called Vark,  or varak (also a silver leaf, German paper) is any leaf composed of pure metals, typically silver but sometimes gold, used on South Asian sweets. The silver is edible, though flavourless.


Hence, the correct option is $C$.