Class 10 Science - Chapter Metals and Non-Metals NCERT Solutions | Give reasons (a) Platinum, gold and s
Give reasons
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
(a) Platinum, gold, and silver are used to make jewellery because they are very lustrous as well as they are very less reactive and do not corrode easily.
(b) Sodium, potassium, and lithium are very reactive metals and react very vigorously with air and water. So, they are kept in kerosene oil in a way to prevent their direct contact with air and moisture.
(c) Aluminium is a reactive metal, yet it can resistant to corrosion. This is because aluminium reacts with oxygen present in air to form aluminium oxide. This oxide layer is quite stable and which further prevents reaction of aluminium with oxygen. Also, it is lightweight and a good conductor of heat. Therefore why it is used to make cooking utensils.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction because metals can be more easily extracted from their oxides than from their carbonates and sulphides.
More Questions From Class 10 Science - Chapter Metals and Non-Metals
- Q:-
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat. - Q:-
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(i) iron with steam
(ii) calcium and potassium with water. - Q:-
(i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii) Show the formation of Na2O and MgO by the transfer of electrons.
(iii) What are the ions present in these compounds?
- Q:-
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal Iron(II) sulphate Cooper(II) sulphate Zinc sulphate Silver nitrate A No reaction Displacement B Displacement No reaction Displacement C No reaction No reaction No reaction No reaction - Q:-
You are given a hammer, a battery, a bulb, wires and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals. - Q:-
Food cans are coated with tin and not with zinc because
(a) zinc is costlier than tin.
(b) zinc has a higher melting point than tin.
(c) zinc is more reactive than tin.
(d) zinc is less reactive than tin. - Q:-
Why do ionic compounds have high melting points?
- Q:-
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
Metal Zinc Magnesium Copper Zinc oxide Magnesium oxide Cooper oxide In which cases will you find displacement reactions taking place?
- Q:-
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
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Why is sodium kept immersed in kerosene oil?
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