question_answer 1)

Describe the bulk preparation of dihydrogen by electrolytic method. What is the role of an electrolyte in this process?

Answer:

Water is a bad conductor of electricity. Water is made a conductor either by addition of an acid or an alkali. The water containing a small amount of an acid or alkali (about 15-20%) is electrolysed in an electrolytic cell. The anode and cathode are separated by asbestos diaphragm. The cathode used is usually of iron and anode usually of nickel. The process is used at places where electric supply is cheap and easily available. Water containing sulphuric acid Ions present are\[{{H}^{+}}\], \[O{{H}^{-}}\] and\[SO_{4}^{2-}\]. On passing electricity \[{{H}^{+}}\]ions move towards cathode while \[OH\]and\[SO_{4}^{2-}\] ions move towards anode. At cathode : Hydrogen ions are discharged to give dihydrogen gas. \[2{{H}^{+}}+2e\to 2H\to {{H}_{2}}\] At anode: \[O{{H}^{-}}\] ions are discharged to give oxygen gas. \[O{{H}^{-}}\to OH+e\] \[4OH\to 2{{H}_{2}}O+{{O}_{2}}\] [\[SO_{4}^{2-}\] ions are not discharged on anode as their discharge potential is higher than that of \[O{{H}^{-}}\] ions.]