5 With the help of an activity explain that hydrogen and oxygen are released when an electric
current is passed through water
Answers
(i)Take a plastic vessel. Drill two holes at its bottom and set rubber stoppers in these holes.
(ii) Insert carbon electrodes in these rubber stoppers and connect these electrodes to a 6 volt battery and a switch.
(iii) Fill the vessel with water such that the electrodes are immersed. Add a few drops of dilute sulphuric acid to the water in the vessel.
(iv) Take two graduated test tubes filled with water and invert them over the two carbon electrodes.
(v) Switch on the current.
(vi) After sometime, you will observe the formation of bubbles at both the electrodes. These bubbles displace water in the graduated tubes.
(vii) Once the test tubes are filled with the respective gases. remove them carefully.
(viii) Test these gases one by one by bringing a burning splinter of wood close to the mouth of test tubes. When the glowing splinter of wood is brought close to the mouth of one test tube. It relights and when it is brought close to the mouth of other test tube the gas burns with a pop. Oxygen is the only common gas that relights the splinter and hydrogen gas burns with a pop.