Concentration of ions in the solution
- 1. (b) Concentration of ions in the solution / electrolytes. Sodium chloride solution, 1.0 mol dm-3 Carbon electrodes Figure 3 Electrolysis of sodium chloride solution From sodium chloride Na+, Cl- From water H+ , OH- CATHODE: Na+ , H+ ANODE: Cl- , OH- Both types of cations are attracted to the Both ions are attracted to the anode, Chloride cathode, H+ ions are selected for discharged ions are discharged because the concentration as they are lower in the ES. of Cl- ions are higher than of OH- ions. 2H+ + 2e -- H2 (g) 2Cl- -- Cl2 (g) + 2e Gas bubbles are formed. When a lighted Bubbles pungent yellowish-green gas is wooden splinter is place near the mouth of produced. The gas changed the damp blue the test tube, a `pop` sound is produced. litmus paper to red and bleached it. Chlorine Hydrogen gas is evolved. gas is formed. Solution becomes alkaline by presence of sodium hydroxide. NaOH(aq)