Give reasons:
a) Why is pure gold not suitable for making ornaments?
b) Why calcium is found in the form of compound?
c) Why electrical wires are coated with PVC (Poly Vinyl Chloride)?
d) Why do we apply oil on iron tools kept in storage?
e) Why sodium is stored in kerosene oil?
a)Ornaments made from 24−carat gold(pure gold) are very rare since pure gold is very soft and is prone to wear and tear upon usage. Hence 22−carat gold is generally used which contains a slight amount of copper, silver and other metals in order to impart wear resistance and at the same time retain its elegance.
b)Calcium and magnesium are reactive elements as they readily losses their two electrons in order to complete their octet. Hence, they are quite reactive and found in the combined state with non metals.
c) In order to distinguish between the live wire, neutral wire and earth wire the wires are provided with different coloures of insulated covering. PVC is an insulator. So, it is used to make it shock free.
d)Iron articles are oiled because it prevents them from rusting. When oiled , the contact of iron articles from moisture and air is cut off. Hence, rusting is prevented.
e)Sodium metal is very reactive. It reacts vigorously with oxygen and water. A lot of heat is generated in this reaction. Hence, it is stored in kerosene.