Activity 1.7
At cathode
(-ve electrode), hydrogen gas is collected. At anode (+ve
electrode), oxygen is collected.
- Take a plastic mug. Drill two holes at its base and fit rubber stoppers in these holes. Insert carbon electrodes in these rubber stoppers as shown in Fig. 1.6.
- Connect these electrodes to a 6 volt battery.
- Fill the mug with water such that the electrodes are immersed. Add a few drops of dilute sulphuric acid to the water.
- Take two test tubes filled with water and invert them over the two carbon electrodes.
- Switch on the current and leave the apparatus undisturbed for some time.
- You will observe the formation of bubbles at both the electrodes. These bubbles displace water in the test tubes.
- Is the volume of the gas collected the same in both the test tubes? (No)
- Once the test tubes are filled with the respective gases, remove them carefully.
- Test these gases one by one by bringing a burning candle close to the mouth of the test tubes.
- What happens in each case?
- Which gas is present in each test tube?
Answer:
When we bring a burning candle to the gas at cathode, it burns immediately. But gas at anode does not burn.
At cathode, double
amount of gas is collected as compared to anode because during the break down
of water, 2H molecule is released with 1 oxygen molecule.