Equal volumes of hydrogen and chlorine are exposed to diffused sunlight to prepare

1. hydrogen chloride
2. water
3. sodium hydroxide
4. hydrochloric acid

The metal which reacts with cold water to produce hydrogen is

1. magnesium
2. aluminium
3. calcium
4. iron

Hydrogen is responsible for producing

1. heat and light
2. hydrogenated oil
3. fertilizers
4. all of the above

Hydrogen is

1. combustible
2. non-combustible
3. supporter of combustion
4. neither supporter nor combustible