Alloying is a very good method of improving the properties of a metal. We can get the desired properties by this method. For example, iron is the most widely used metal. But it is never used in its pure state. This is because pure iron is very soft and stretches easily when hot. But, if it is mixed with a small amount of carbon (about 0.05%), it becomes hard and strong.
i. When iron is mixed with nickel and chromium, we get:
a) Chromium steel
b) Gun metal
c) Stainless steel
d) None
ii. Alloying is done:
a) To enhance the properties of a metal
b) To make metal were lustrous
c) To make metal stronger
d) All
iii. We know alloying is done to make the metal rust free. When iron is coated with zinc, process is called:
a) Electroplating
b) Tinning
c) Galvanisation
d) All
iv. The galvanised article is protected against rusting even if the zinc coating is broken. This is because:
a) Article being more reactive
b) Zinc being more electropositive and hence reactive
c) Zinc is highly electronegative d) None
v. We don’t want gold to be of 24 carats, as it is very soft. To make it suitable for jewellery, we alloy gold with:
a) Copper
b) Silver
c) Both a and b
d) None
