1)Write an equation showing how aluminium oxide dissolves in sodium hydroxide
2)Why is carbon(iv)oxide bubbled through the filtrate?Write equation for the above reaction
3)Write an equation to show how aluminium oxide is obtained from aluminium
4)When aluminium oxide is placed in the cell,name the product at the cathode and anode
5)Name the substance that lowers the melting point of aluminium oxide and show its formula
6)Name the material used as cathode and anode rods.Explain why
7)Why should carbon rods be replaced from time to time
1) Al2O3 (s) + 2NaOH (aq) → 2NaAlO2 (aq) + H2O (l)
2) Carbon(iv) oxide is bubbled through the filtrate to remove any excess sodium hydroxide present. The reaction that occurs is: CO2 (g) + 2NaOH (aq) → Na2CO3 (aq) + H2O (l)
3) 2Al (s) + 3O2 (g) → 2Al2O3 (s)
4) At the cathode, the product is aluminum metal (Al) and at the anode, the product is oxygen gas (O2).
5) The substance that lowers the melting point of aluminum oxide is cryolite (Na3AlF6), with the formula being Na3AlF6.
6) Graphite is commonly used as the material for cathode and anode rods because it is chemically stable and has a high melting point. It is also a good conductor of electricity, allowing for efficient electrolysis.
7) Carbon rods should be replaced from time to time because they gradually erode during the electrolysis process, which can lead to reduced efficiency and contamination of the electrolyte.