NCERT Solutions Science Chapter 4 Metals and Non-Metals for Class 8th
Chapter 4 of the NCERT Science textbook for Class 8, titled “Metals and Non-Metals,” explores the distinct properties and uses of metals and non-metals. Metals, such as iron, copper, and aluminum, are characterized by their luster, malleability, ductility, and good conductivity of heat and electricity. They typically form basic oxides and can displace hydrogen from acids. In contrast, non-metals like sulfur, carbon, and oxygen exhibit varying properties, often being dull, brittle, and poor conductors of heat and electricity. Non-metals can form acidic or neutral oxides and do not react with acids to release hydrogen. The chapter also discusses the reactivity series, which ranks metals based on their reactivity, and highlights the importance of metals and non-metals in everyday life, including their roles in construction, electronics, and biological systems. Understanding these differences helps in comprehending their applications in various fields.
NCERT Solutions Science Chapter 4 Metals and Non-Metals
1. Which of the following can be beaten into thin sheets?
(a) Zinc
(b)Phosphorus
(c) Sulphur
(d) Oxygen
Answer- (a)
2. Which of the following statements is correct?
(a) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.
Answer – (c)
3. Fill in the blanks.
(a) Phosphorus is a very _________non-metal.
(b) Metals are conductors of heat and ____________ .
(c) Iron is ____________reactive than copper.
(d) Metals react with acids to produce ____________ gas.
Answer
(a) Phosphorus is a very reactive non-metal.
(b) Metals are good conductors of heat and electricity.
(c) Iron is more reactive than copper.
(d) Metals react with acids to produce hydrogen gas.
4. Mark ‘T’ if the statement is true and ‘F’ if it is false.
(a) Generally, non-metals react with acids. ( )
(b) Sodium is a very reactive metal. ( )
(c) Copper displaces zinc from zinc sulphate solution. ( )
(d) Coal can be drawn into wires. ( )
Answer:
a) False
b) True
c) False
d) False
5. Some properties are listed in the following table. Distinguish between metals and non-metals on the basis of these properties.
Answer:
| Properties | Metals | Non-metals |
| 1. Appearance | Lustrous | Dull |
| 2. Hardness | Hard | Soft |
| 3. Malleability | Have property of Malleability | Do not have a property of Malleability |
| 4. Ductility | Have property of Ductility | Do not have the property of Ductility |
| 5. Heat Conduction | Good conductor of Heat | Bad Conductor of Heat |
| 6. Conduction of Electricity | Good conductor of Electricity | The bad conductor of Electricity |
6. Give reasons for the following.
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene
Answer:
a) Aluminium is malleable and can be drawn into thin sheets hence Aluminium foils are used to wrap food items
b) Immersion rods for heating liquids are made up of metallic substances because metals are good conductors of heat and electricity.
c) Copper cannot displace zinc from its salt solution because Zinc is more reactive than copper.
d) Sodium and Potassium are highly reactive metals which readily reacts with atmospheric Oxygen to catch fire hence Sodium and Potassium are stored in kerosene.
7. Can you store the lemon pickle in an aluminium utensil? Explain.
Answer:
Pickle consists of acids which react with Aluminium metal to produce salt and Hydrogen. Hence pickle is not stored in aluminium utensil.
8. Match the substances given in Column A with their uses given in Column B.
| A | B |
| (i) Gold | (a) Thermometers |
| (ii) Iron | (b) Electric wire |
| (iii) Aluminium | (c) Wrapping food |
| (iv) Carbon | (d) Jewellery |
| (v) Copper | (e) Machinery |
| (vi) Mercury | (f) Fuel |
Answer:
| A | B |
| (i) Gold | (d) Jewellery |
| (ii) Iron | (e) Machinery |
| (iii) Aluminium | (c) Wrapping food |
| (iv) Carbon | (f) Fuel |
| (v) Copper | (b) Electric wire |
| (vi) Mercury | (a) Thermometers |
9. What happens when
(a) Dilute sulphuric acid is poured on a copper plate?
(b) Iron nails are placed in a copper sulphate solution?
Write word equations of the reactions involved.
Answer:
(i) No reaction occurs when dilute sulphuric acid is poured on a copper plate. However, when concentrated sulphuric acid is poured on a copper plate, hydrogen gas evolves along with the formation of blue coloured copper sulphate crystals. The chemical reaction for the reaction between concentrated sulfuric acid and copper is:
Cu + H2SO4 (conc.) -> CuSO4 + H2
ii) Iron being more reactive displaces copper from copper sulphate. In this reaction, the blue colour of copper sulphate fades and there is a deposition of copper on the iron nail.
Fe + CuSO4 → FeSO4 + Cu
10. Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(a) How will she find the nature of the gas?
(b) Write down word equations of all the reactions taking place in this process.
Answer: a) In a test tube containing gas, add a few drops of water. Now cover the test tube and shake well. After shaking, test the solution with blue litmus. It will change from blue to red. Thus, gas is acidic in nature.
b) Charcoal reacts with oxygen to form carbon dioxide gas.