Metals and Non-metals
Reaction with Acids
Metals generally react with acids and produce hydrogen gas. This reaction can be shown by a general equation which is given below.
Metal + Acid → Salt + Hydrogen
Example: When hydrochloric acid is poured over zinc granules then zinc chloride and hydrogen gas are formed. Here, zinc chloride is a salt.
Zn + 2HCl → ZnCl2 + H2
Testing for Hydrogen Gas
Confirmation of hydrogen gas is done by bringing a burning matchstick or a burning candle near the gas. When the burning matchstick or candle burns with a pop sound it confirms the evolution of hydrogen gas.
Other Metals and Acid
Sodium, calcium, potassium and zinc readily react with acids. But other metals do not react with acids. Copper does not react with even concentrated hydrocholoric acid. However, copper reacts with concentrated sulphuric acid. Iron, gold and silver do not react with acids at all.
Non-metals generally do not react with acids.
Reaction with Bases
Metals react with sodium hydroxide to produce hydrogen gas.
Metal + Sodium hydroxide → Hydrogen
Non-metals' reaction with sodium hydroxide is much complex.
When a metal displaces another metal from a compound, this is called displacement reaction. In this reaction, a more reactive metal displaces a less reactive metal from a compound.
Reactivity Series: Metals can be arranged in chronological order, on the basis of their reactivity. Such an arrangement of metals is called reactivity series of metals. Sodium and potassium are at the top of the reactivity series. Gold and silver are at the bottom of reactivity series.
Example: When zinc granules are kept in copper sulphate solution, the blue colour of copper sulphate disappears and the solution becomes colourless. Zinc is more reactive than copper and hence displaces copper from copper sulphate solution and forms zinc sulphate.
CuSO4 + Zn → ZnSO4 + Cu
But when copper turnings are kept in zinc sulphate solution, no reaction takes place. In this case, reaction is not possible because copper is less reactive than zinc.
Example: When iron nails are kept in copper sulphate solution, the blue colour of copper sulphate solution disappears and the solution becomes green. Iron is more reactive than copper and hence it displaces copper from copper sulphate solution and forms iron sulphate.
CuSO4 + Fe → FeSO4 + Cu
But when copper turnings are kept in iron sulphate solution, no reaction takes place. In this case, reaction is not possible because copper is less reactive than iron.
Uses of Metals:
Metals are very useful for us. Minute quantities of various metals are necessary for our body. For example, iron is an important component of blood. Calcium is the building block of our bones. Metals are used for various tools and appliances. Some examples of uses of metals are given below.
- Metals are used for making machines and tools.
- Iron is used for making ships, bridges, railway lines, etc.
- Copper is used for making electric wires.
- Aluminium is used for making utensils.
- Gold and silver are used for making ornaments.
Uses of Non-metals:
Non-metals are also useful for us. They are required by living beings for various processes. Some examples of uses of non-metals are given below.
- Oxygen is used by all living beings for respiration.
- Carbon dioxide is used by plants for photosynthesis.
- Chlorine is used for water purification.
- Iodine solution is used as antiseptic and applied on wounds.
- Coal (carbon) is an important fuel.