Page No 54: - Chapter 4 Metals & Non Metals class 8 ncert solutions Science - SaraNextGen [2024-2025]
Updated By SaraNextGen
On April 24, 2024, 11:35 AM
Question 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.
Question 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:
(i) Generally, non-metals react with acids. (F)
(ii) Sodium is a very reactive metal. (T)
(iii) Copper displaces zinc from zinc sulphate solution. (F)
(iv) Coal can be drawn into wires. (F)
Question 5:
Some properties are listed in the following Table. Distinguish between metals and non-metals on the basis of these properties.
|
Properties |
Metals |
Non-metals |
|
1. Appearance 2. Hardness 3. Malleability 4. Ductility 5. Heat Conduction 6. Conduction of Electricity |
Answer:
|
Properties |
Metals |
Non-metals |
|
1. Appearance2. Hardness 3. Malleability 4. Ductility 5. Heat conduction 6. Conduction of electricity |
Lustrous Hard Can be beaten into thin sheets Can be drawn into wires Good conductors of heat Good conductors of electricity |
Dull Soft Cannot be beaten into thin sheets Cannot be drawn into wires Poor conductors of heat Poor conductors of electricity |
Give reasons for the following.Question 6:
(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 foils are used to wrap food items because aluminium metal is malleable. Therefore, it can be beaten into thin foils.
(b) Metals are good conductors of heat and electricity. Therefore, immersion rods for heating liquids are made of metallic substances.
(c) A metal can displace a less reactive metal from its salt in an aqueous solution. But zinc is more reactive than copper. Therefore, copper cannot displace zinc from its salt solution.
Cu(s) + ZnSO4 (aq) → No reaction
(d) Sodium and potassium are stored in kerosene because they are highly reactive elements. They can easily catch fire even when in contact with air.
Question 7:
Can you store lemon pickle in an aluminium utensil? Explain.
Answer:
Lemon pickle cannot be stored in aluminium utensils because lemon pickle contains acids, which can react with aluminium (metal) liberating hydrogen gas. This can lead to the spoiling of the pickle.
Question 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 |
Also Read : Page-No-55:-Chapter-4-Metals-&-Non-Metals-class-8-ncert-solutions-Science
