{"id":24830,"date":"2021-06-21T14:34:17","date_gmt":"2021-06-21T09:04:17","guid":{"rendered":"https:\/\/mcq-questions.com\/?p=24830"},"modified":"2022-03-02T10:38:08","modified_gmt":"2022-03-02T05:08:08","slug":"ncert-solutions-for-class-8-science-chapter-4","status":"publish","type":"post","link":"https:\/\/mcq-questions.com\/ncert-solutions-for-class-8-science-chapter-4\/","title":{"rendered":"NCERT Solutions for Class 8 Science Chapter 4 Materials: Metals and Non-Metals"},"content":{"rendered":"

These NCERT Solutions for Class 8 Science<\/a> Chapter 4 Materials: Metals and Non-Metals Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.<\/p>\n

Materials: Metals and Non-Metals NCERT Solutions for Class 8 Science Chapter 4<\/h2>\n

Class 8 Science Chapter 4 Materials: Metals and Non-Metals Textbook Exercise Questions and Answers<\/h3>\n

Page 53-55<\/span><\/p>\n

Question 1.
\nWhich of the following can be beaten into thin sheets?
\na. Zinc
\nb. Phosphorus
\nc. Sulphur
\nd. Oxygen
\nAnswer:
\na. Zinc<\/p>\n

Question 2.
\nWhich of the following statements is correct?
\na. All metals are ductile.
\nb. All non-metals are ductile.
\nc. Generally, metals are ductile.
\nd. Some non-metals are ductile.
\nAnswer:
\nc. Generally, metals are ductile.<\/p>\n

Question 3.
\nFill in the blanks:
\na. Phosphorus is a very …………….. non-metal.
\nb. Metals are …………….. conductors of heat and ……………..
\nc. Iron is …………….. reactive than copper.
\nd. Metals react with acids to produce …………….. gas.
\nAnswer:
\na. reactive,
\nb. good, electricity,
\nc. more,
\nd. hydrogen<\/p>\n

Question 4.
\nMark \u2018T\u2019 if the statement is true and \u2018F\u2019 if it is false.
\na. Generally, non-metals react with acids. ( )
\nb. Sodium is a very reactive metal. ( )
\nc. Copper displaces zinc from zinc sulphate solution. ( )
\nd. Coal can be drawn into wires. ( )
\nAnswer:
\na. False
\nb. True
\nc. False
\nd. False<\/p>\n

\"NCERT<\/p>\n

Question 5.
\nSome properties are listed in the following table. Distinguish between metals and non-metals on the basis of these properties.<\/p>\n\n\n\n\n\n\n\n\n\n
\n

Properties<\/p>\n<\/td>\n

Metals<\/td>\nNon-metals<\/td>\n<\/tr>\n
1. Appearance<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
2. Hardness<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
3. Malleability<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
4. Ductility<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
5. Heat Conduction<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
6. Conduction of N Electricity<\/td>\n<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Answer:<\/p>\n\n\n\n\n\n\n\n\n\n
\n

Properties<\/p>\n<\/td>\n

Metals<\/td>\nNon-metals<\/td>\n<\/tr>\n
1. Appearance<\/td>\nLustrous<\/td>\nDull<\/td>\n<\/tr>\n
2. Hardness<\/td>\nHard<\/td>\nSoft<\/td>\n<\/tr>\n
3. Malleability<\/td>\nCan be beaten into thin sheets have property of Malleability<\/td>\nCannot be beaten into thin sheets<\/td>\n<\/tr>\n
4. Ductility<\/td>\nCan be drawn into wires<\/td>\nCannot be drawn into wires<\/td>\n<\/tr>\n
5. Heat Conduction<\/td>\nGood conductors of heat<\/td>\nPoor conductors of heat<\/td>\n<\/tr>\n
6. Conduction of Electricity<\/td>\nGood conductors of electricity<\/td>\nPoor conductors of electricity<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 6.
\nGive reasons for the following:
\na. Aluminium foils are used to wrap food items.
\nb. Immersion rods for heating liquids are made up of metallic substances.
\nc. Copper cannot displace zinc from its salt solution.
\nd. Sodium and potassium are stored in kerosene.
\nAnswer:
\na. Aluminium reacts with air to make a coating of aluminium oxide on it. This layer prevents aluminium from further reactions with any substance. Due to this, aluminium foils are used to wrap food items because it does not react with food.<\/p>\n

b. Metals are good conductors of heat and have a high melting point. Immersion rods need to heat up quickly and should not melt at high temperatures. Hence, immersion rods for heating liquids are made up of metallic substances.<\/p>\n

c. Copper is less reactive than zinc. Hence, copper cannot displace zinc from its salt solution.<\/p>\n

d. Sodium and potassium are highly reactive and react vigorously with water even at room temperature. The reaction is highly exothermic and the reaction mixture instantly catches fire. Sodium and potassium are stored in kerosene to prevent this reaction and to prevent accidental fire.<\/p>\n

Question 7.
\nCan you store lemon pickle in an aluminium utensil? Explain.
\nAnswer:
\nNo, it is not possible to store lemon pickle in an aluminium utensil because lemon pickle is acidic and can react with aluminium (metal) liberating hydrogen gas. This may spoil the pickle.<\/p>\n

Question 8.
\nMatch the substances given in Column A with their uses given in Column B.<\/p>\n\n\n\n\n\n\n\n\n\n
Column A<\/td>\nColumn B<\/td>\n<\/tr>\n
i. Gold<\/td>\na. Thermometers<\/td>\n<\/tr>\n
ii. Iron<\/td>\nb. Electric wire<\/td>\n<\/tr>\n
iii. Aluminium<\/td>\nc. Wrapping food<\/td>\n<\/tr>\n
iv. Carbon<\/td>\nd. Jewellery<\/td>\n<\/tr>\n
v. Copper<\/td>\ne. Machinery<\/td>\n<\/tr>\n
vi. Mercury<\/td>\nf. Fuel<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Answer:
\n(i) \u2192 d,
\n(ii) \u2192 e,
\n(iii) \u2192 c,
\n(iv) \u2192 f,
\n(v) \u2192 b,
\n(vi) \u2192 a<\/p>\n

\"NCERT<\/p>\n

Question 9.
\nWhat happens when
\na. Dilute sulphuric acid is poured on a copper plate?
\nb. Iron nails are placed in copper sulphate solution?
\nWrite word equations of the reactions involved.
\nAnswer:
\na. Copper does not react with dilute sulphuric acid. So, no reaction takes place when dilute sulphuric acid is poured on a copper plate. However, when concentrated sulphuric acid is poured on copper plate, hydrogen gas evolves along with the formation of blue coloured copper sulphate crystals.
\nCu + H2<\/sub>SO4<\/sub> (conc.) \u2192 CuSO4<\/sub> + H2<\/sub>O
\nCopper + Dilute sulphuric acid \u2192 No reaction<\/p>\n

b. When iron nails are placed in copper sulphate solution, the blue colour of copper sulphate solution is replaced by a light green colour. This happens because, iron being more reactive than copper, displaces copper from copper sulphate and makes iron sulphate solution.
\nCopper sulphate (blue) + Iron \u2192 Iron sulphate (light green) + Copper
\nFe + CuSO4<\/sub> \u2192 FeSO4<\/sub> + Cu<\/p>\n

Question 10.
\nSaloni took a piece of burning charcoal and collected the gas evolved in a test tube.
\na. How will she find the nature of the gas?
\nb. Write down word equations of all the reactions taking place in this process.
\nAnswer:
\na. Saloni should bring a wet blue litmus paper near the evolved gas. If litmus paper turns to red, it indicates that the evolved gas is acidic in nature.<\/p>\n

b. Carbon (in charcoal) reacts with oxygen to produce carbon dioxide gas.
\nC + O2<\/sub> \u2192 CO2<\/sub>
\nCarbon dioxide reacts with water to form carbonic acid.
\nCO2<\/sub> + H2<\/sub>O \u2192 H2<\/sub>CO3<\/sub> (acidic)<\/p>\n

Question 11.
\nOne day Reeta went to a jeweller\u2019s shop with her mother. Her mother gave old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight?
\nAnswer:
\nJewellers use aqua regia to clean the jewellery. Gold is an inert metal which does not react with acids. But aqua regia is a mixture of hydrochloric acid and nitric acid in 3 : 1 ratio. It is so potent that it even dissolves gold and silver. Some of the gold is thus lost during the cleaning of jewellery. This explains the weight loss in jewellery.<\/p>\n

NCERT Extended Learning Activities and Projects<\/span><\/p>\n

Question 1.
\nPrepare Index Cards for any four metals and four non-metals. The card should have information like name of metal\/non-metal; its physical properties, chemical properties and its uses.
\nHint:
\nUses of Metals<\/p>\n