1 Each square on the map is 2 cm by 2 cm (4 cm 2) and represents 1 km 2 on the surface of the earth. 2  For 1:25,000 maps, the grid lines are 4 cm apart. 3  Each square on the map is 4 cm by 4 cm (16 cm 2) and represents 1 km 2 on the surface of the earth.
+ 2 e â + 2 H + â. In the last example, H + ions (hydrogen ions) also take part in the reaction, and are provided by an acid in the solution, or by the solvent itself (water, methanol etc.). Electrolysis reactions involving H + ions are fairly common in acidic solutions.
It contains positively charged sodium ions and negatively charged chloride ions. Ionic substances can be broken down by electricity. Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them.