Distinguish between the following substances.
Distinguish between the following substances. Give the equations where appropriate. Flame test is NOT accepted.
(a) Sodium sulphate and sodium sulphite.
(b) Aluminium oxide and zinc oxide.
(c) zinc nitrate solution and potassium nitrate solution.
(d) Ammonium sulphate solution and sodium sulphate solution.
- Gabriella MontezLv 71 十年前最愛解答
a) Add aqueous chlorine solution ( or any other aqueous solutions of halogens ) to the two samples. The one which turns aqueous chlorine solution from pale green to colourless is sodium sulphite. It is due to a redox reaction.
Cl2 + ( 2e- ) ---> (2Cl-) ***** ( reduction )
( SO3 2- ) + H2O ---> ( SO4 2- ) + ( 2H+ ) + ( 2e- ) ***** ( oxidation )
Overall equation : Cl2 + ( SO3 2- ) + H2O ---> (2Cl-) + ( SO4 2- ) + ( 2H+ )
b) Heat the two oxides with carbon and the one which gives out carbon dioxide is zinc oxide.
2ZnO + C ---> 2Zn + CO2
c) Test the two solutions with aqueous sodium hydroxide. The one which gives a jelly-like white precipitate is zinc nitrate solution.
Zn + ( 2OH-) ---> Zn(OH)2
d) Warm the two solutions with aqueous sodium hydroxide solution. The one which gives a fishy smell is ammonium sulphate solution.
( NH4+) + (OH-) ---> NH3 + H2O
Hope it helps.資料來源： My Chemistry Knowledge