General Science - Elements and Metals

1.Brass gets discoloured in air because of the presence of which of the following gases in air?

Oxygen Hydrogen sulphide Carbon dioxide Nitrogen

2.Which of the following is a non metal that remains liquid at room temperature?

Phosphorous Bromine Chlorine Helium

3.Chlorophyll is a naturally occurring chelate compound in which central metal is

copper magnesium iron calcium

4.Which of the following is used in pencils?

Graphite Silicon Charcoal Phosphorous

5.Which of the following metals forms an amalgam with other metals?

Tin Mercury Lead Zinc