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

Metals found at the top of the reactivity series are never found in free-state because

  1. They are less reactive

  2. They are highly reactive

  3. They are moderately reactive

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

Metals found at the top of the reactivity series are never found in free-state as they are very reactive, e.g. K, Na, Ca, Mg and Al, etc.

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

Which of the following are found as carbonate ore in nature?

  1. $Fe$
  2. $Mg$
  3. $Zn$
  4. $Pb$
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

 Carbonate ores are Magnesite $(MgCO _3)$, Dolomite $(CaCO _3MgCO _3)$, Calamine $(ZnCO _3)$, Malachite $(CuCO _3.Cu (OH) _2)$, Siderite $(FeCO _3)$, and Limestone $(CaCO _3)$.

A principal ore of lead is galena $(PbS)$.

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

 Copper is extracted from sulphide ore using the method:

  1. Carbon reduction

  2. Carbon monoxide reduction

  3. Auto reduction

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
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 $C$
Multiple choice chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

Which of the following are sulphate ores?

  1. Cinnabar

  2. Gypsum

  3. Galena

  4. Iron pyrite
Reveal answer Fill a bubble to check yourself
B Correct answer
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 $(FeS _2)$. 

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

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

  1. $FeSO _4$
  2. $FeSiO _3$
  3. $Fe3O _4$
  4. $Fe _2O _3$
Reveal answer Fill a bubble to check yourself
B Correct answer
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.
$CuFeS _2 + SiO _2 + 4O _2 \rightarrow Cu _2S + 2FeSiO _3 + 3SO _2$