Chapter 3 · Metals and Non-metals

NCERT Class 10 Science Chapter 3 Intext Questions (Page 53)

All 3 questions of NCERT Class 10 Science Chapter 3 Intext Questions (Page 53) — Metals and Non-metals — in the book's order, each with its answer and a step-by-step solution.

1. Q1
   Define ​the following ​terms.

   1. (i)​Mineral
   2. (ii)Ore
   3. (iii)Gangue
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   Minerals occur naturally in the earth's crust; an ore is a mineral that yields metal profitably; gangue is the impurity in an ore.

   (i) Mineral: the elements or compounds which occur naturally in the earth's crust are called minerals. (ii) Ore: a mineral that contains a very high percentage of a particular metal, from which the metal can be extracted profitably, is called an ore (for example, cinnabar, HgS, is an ore of mercury). (iii) Gangue: the impurities such as soil, sand and rocky material with which an ore is contaminated when it is mined from the earth are called gangue; they are removed from the ore before the metal is extracted.

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2. Q2
   Name two metals ​which ​are ​found ​in ​nature in the ​free state.
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   Gold and silver are found free in nature because they are unreactive.

   Gold (Au) and silver (Ag) are found in nature in the free state. (Platinum and copper are also found free; copper and silver additionally occur in the combined state as sulphide or oxide ores.)

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3. Q3
   What chemical ​process is ​used ​for ​obtaining a metal from its ​oxide?
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   Reduction: the metal oxide is reduced, e.g. by carbon, to give the metal.

   Reduction. A metal is obtained from its oxide by reducing the oxide (removing its oxygen) with a suitable reducing agent: carbon for metals in the middle of the activity series, e.g. $\text{ZnO(s)}+\text{C(s)}\to \text{Zn(s)}+\text{CO(g)}$; a more reactive metal such as aluminium (thermit reaction), e.g. ${\text{Fe}}_2{\text{O}}_3\text{(s)}+2\text{Al(s)}\to 2\text{Fe(l)}+{\text{Al}}_2{\text{O}}_3\text{(s)}+\text{heat}$; heating alone for the least reactive metals, e.g. $2\text{HgO(s)}\stackrel{\text{heat}}{\to }2\text{Hg(l)}+{\text{O}}_2\text{(g)}$; and electrolytic reduction for the most reactive metals (Na, Mg, Ca, Al).

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