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 as these metals are very less reactive. Hence, they are not affected by air, water or most chemicals. These metals have a lot of luster and they are malleable and ductile in nature, and also high corrosion resistance in nature.
(b) Sodium, potassium and lithium readily react with water to produce a lot of heat. As a result, hydrogen evolved in the reaction results in a fire. On exposure to water they react with moisture (water droplets) present in the atmosphere, in order to prevent contact with water. Hence, these metals are stored under oil.
(c) Aluminium forms on its surface a nonreactive surface of aluminium oxide. Such coating prevents other compounds from reacting to aluminium. So aluminium is used to produce utensils for cooking.
(d) Reducing metal oxide into free metal is easy. Additionally, because it is easier to obtain metals directly from their oxides than from their carbonates or sulphides, the carbonate and sulphide ores are first transformed to oxides to obtain the metals.
Suggested Q&A
Science · Class 10- ScienceClass 10Explain why generally metals are solid at room temperature, but mercury is a liquid.
- ScienceClass 10What is the role of a flux in the metallurgical process?
- ScienceClass 10Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
- ScienceClass 10A 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?
- ScienceClass 10Differentiate between metal and non-metal on the basis of their chemical properties.
- ScienceClass 10You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
- ScienceClass 10What type of oxides are formed when non-metals combine with oxygen?
- ScienceClass 10State two ways to prevent the rusting of iron.
- ScienceClass 10Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below. (a) What will be the action of gas on (i) dry litmus paper? (ii) moist litmus paper? (b) Write a balanced chemical equation for the reaction taking place.
- ScienceClass 10In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?