Give reasons of each
(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) Calcium floats on water.
(e) Milk of magnesia treats acidity.
Answers
Answer:
Explanation:
(a) Platinum, gold and silver are used to make jewellery because these are low reactive metals. So they rarely corrode and hence do not lose their shine and lustre.
(b) The reaction of these substances with oxygen is highly exothermic which may cause fire, also they react with water to form base so they are kept in oil.
(c) This is because aluminium is good conductor of heat and electricity. To prevent its reaction with food at high temperature a protective layer of aluminium oxide (Al
2
O
3
) is formed which prevent further corrosion.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction because it is easier to obtain metal from its oxide as compared with its sulphides or carbonates ore.
Answer:
a) Platinum, gold and silver are used to make jewellery because the metals used in jewellery are always be chosen on the basis of its reactivity. ... They are highly lustrous metals which are resistant to corrosion. They are highly malleable and ductile so can be transformed into any shape or design..
b)Sodium, potassium, and lithium are stored under oil because metals like sodium and potassium react so, vigorously that they catch fire if kept in the open. Hence, to protect them they are kept immersed in kerosene oil.
c)Aluminium metal forms a thin layer of aluminium oxide all over its surface under the action of moist air. This layer prevents the metal underneath from further corrosion. It is cheap, easily available, malleable and ductile. Therefore, it is used to make utensils cooking.
d)The reaction of calcium with water is less violent. So, the heat released is not sufficient for the hydrogen to catch fire. Calcium starts floating because the bubbles of hydrogen gas which are formed during the reaction stick to the surface of the metal and hence calcium floats on water.
e)This medication is also used to treat symptoms caused by too much stomach acid such as heartburn, upset stomach, or indigestion. It is an antacid that works by lowering the amount of acid in the stomach.
Explanation:
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