Metals and Non-Metals / Part II /Reactivity series | Extraction Of Metals from Its Ore |

I) Reactivity Series: - 

          The Arrangement of elements according to their reactivity is called reactivity series.

II) Reaction Of Metals with water.

         Metal react with water to form metal hydroxide and hydrogen gas is released

Metal +water ------->metal hydroxide +hydrogen gas

Na (s) + cold H2O (l) ------------>NaOH (aq)+H2(g)

K (s) + cold H2O (l) ---------> KOH (aq) + H2 (g)

✓Some Metals react with cold water: 

Sodium and Potassium are the metals which reacts with cold water.

✓Some Metals react with hot water: 

Calcium and Magnesium are the metals which reacts with hot water.

Ca (s) + hot H2O (l) --------> Ca(OH)2 (aq)

Mg(s) + hot H20 (l) ----------> Mg(OH)2 (aq)

✓Some metals react with steam:

       Metals like Iron, Zinc and Aluminium react with steam

✓when iron reacts with steam : 

Fe (s)+steam H2O(l)--------->Fe3O4(s) +H2 (g)

✓Some elements don't reacts:- 

Elements below hydrogen in reactivity series like copper, mercury, silver, gold and platinum are less reactive Metals hence cannot displace Hydrogen from acids.

✓Order of reactivity of Metals : 

Na> Mg> Zn> Fe> Cu

III) Reaction of Non-Metals with water: 

Non-Metals do not react with water because they are electron acceptor and cannot donate electron to Hydrogen.

IV) Reaction of Metal with dilute acids:-

Metals react with acids to form salt and hydrogen gas is released

Example:- 

1) H2So4(aq) + Zn(s) ---------->ZnSo4(aq) + H2 (g)

Reaction of metal with acid

Reason:-

                  Metals below hydrogen in the reactivity series can’t displace hydrogen of acids because they are less reactive then hydrogen.

For displacing, they need to donate electrons to hydrogen but it is not possible because they are themselves electron acceptors.

✓ Reaction of Nitric acid with Metal:-

-Hydrogen gas not evolved when metal reacts with nitric acid because nitric acid strong oxidising agent.

- It oxidises H2 to form water and itself get reduced to any of nitrogen oxides,

-But Mg and Mn reacts with very dilute Nitric acid to evolve H2 gas.

V) Metallurgy:-

metals have good reactivity. So, they generally occur in combined state but few metals that are less reactive occur in free state like platinum ,gold etc. 

✓Minerals: 

Anything that is found in earth’s crust is called mineral.

✓Ores:

 The mineral from which metal can be extracted is called ore.

Note:- All ores are minerals but all minerals are not ores.

✓Different Types of Ores:

a) Oxide ores

b) Halide ores

c) Sulphide ores

d) Carbonate ores

✓Ores of Some Metals:

Aluminium: Bauxite ore, cryolite ore

Iron: Haemtite ore, magnetite ore

Copper: Copper pyrite, copper glance

Zinc: Zinc Blende

Mercury: Cinnabar

✓Metallurgy:- 

It is the process of extracting metal from its ore.

✓Occurrence of ore:-

     Earth crust is the major source of metals

✓Metals at the bottom e.i, lower reactive series elements are least reactive and are found in free state.

Example:- Au, Ag, PT and Cu

Copper and Silver are found in combined state as Sulphides or Oxide Ores.

✓Ores of medium reactive elements are found in Oxides and Sulphides forms in nature .

✓Metals of Top of the activity series are never found in free state.

Example:- K, Na, CA, Mg, and Al

The metals in the middle of the activity series are moderately reactive and are found in earth crust as many as Oxides, Sulphides or Carbonates.

Example:- Zn, Fe, Pb etc.

VI) Various steps involved in metallurgy are as follows -

1) Concentration of ore or Enrichment of Ores

2) Oxidation of ore

3)Reduction of ore

4) Refining

1) Concentration of ore or Enrichment of Ores:-

          Ores contain large amount of impurities such as soil, sand etc and are called gangue. These impurities must be removed from ore for the extraction of metal which is based on physical and chemical properties of gangue and ore.

The process of removing these impurities from ore is called Concentration of Ore or Enrichment of Ore.

✓ Oxidation of ore: It is the process of converting concentrated ore into metal oxide.

The methods involved are calcination and roasting

1) Calcination:-

                  It is the process of heating ore in absence of air to convert Metal Carbonate ore to Metal oxide.

Example : ZnCo3 (s)--------->ZnO (s)+ Co2 (g)

Reduction

ZnO (s) + C (s) --------> Zn (s) + O2 ( g)

This method is used only for carbonate ores.

Calcination

2) Roasting:-

                     it is the process of conversion of Metal Sulphide Ore into a metal Oxide by heating ore in presence of air

 Example: When Cinnabar( HgS) is heated in air, it's convert into mercuric oxide and further mercuric oxide then reduced to mercury on further heating.

HgS( s) + O2 (g) ------> HgO (s) + SO2 (g)

HgO (s) heated-------> Hg (s) + O2 (g)

Roasting

*Displacement reaction use for extraction of metal from ore.

The higher reactive Metals such as Sodium , Calcium, Aluminium etc. are used as reducing agent because they can displace metals of lower reactivity from their compound.

Example:-

When Manganese oxide is heated with Aluminium powder.

3MnO2 (s) + 4Al (s)-------> 2Al2O3 (s) + 3Mn (l)

The displacement reaction are highly exothermic thus the amount of heat evolved is so large that the metals are in molten state.

✓Thermit reaction:-

The displacement reaction of iron(III) oxide [Fe2O3] with aluminium .

Fe2O3 (s) + 2Al ( s)-------> 2Fe (l) + Al2O3 (s) + Heat

✓Use :-

The molten metal is use in joining railway tracks or cracked machine parts.

Social links

1) YouTube :- https://youtube.com/c/Scienceworldacademy

2) Telegram :- https://t.me/scienceworldlearningbegins

3) Blog :- https://cometolearnscience.blogspot.com/2021/06/importance-of-ph-in-everyday-life.html