Seawater contains many salts dissolved in it. Common salt is separated from these salts. Deposits of solidβ¦
Seawater contains many salts dissolved in it. Common salt is separated from these salts. Deposits of solid salt are also found in several parts of the world. These large crystals are often brown due to impurities. This is called rock salt and is mined like coal. The common salt is an important raw material for chemicals of daily use. (a) Write balanced chemical equations to show the products formed during electrolysis of brine. (b) List two uses of any one product obtained during electrolysis of brine. (c) (i) A mild non-corrosive basic salt 'A', used for faster cooking, is strongly heated to produce a compound 'B', that is used for removing permanent hardness of water. Identify A and B and also write the equation for the reaction that occurs when A is heated.
Solution
πππππ‘πππππ‘π¦
(a) 2 πππΆπ + 2 π»2 π β 2 ππππ» + π»2 + πΆπ2
(b)
Uses of NaOH : Degreasing metals/ Soaps and Detergents/ paper
making/ artificial fibres/ preparation of bleach Β½,Β½
Uses of H2: As fuel/ Margarine/ In preparation of ammonia for
fertilizers/Preparation of HCl
Uses of Cl2 : Disinfectant/ PVC/ water treatment/ in swimming
pools/ CFCβs/ preparation of bleach/ preparation of HCl/ pesticides
(Any two uses of anyone product)
(c) (i) A β NaHCO3/ Sodium Hydrogen Carbonate/ Baking
soda
B β Na2CO3 / Sodium Carbonate
βπππ‘
2 πππ»πΆπ3 β ππ2 πΆπ3 + π»2 π + πΆπ2
A B
OR
(c) (ii) β’ The fixed number of water molecules present in
one formula unit of a salt.
β’ CuSO4.5H2O/Copper Sulphate pentahydrate/Blue vitrol
β’ CaSO4.2H2O/Gypsum/Calcium sulphate dihydrate
β’ Na2CO3.10H2O/Washing Soda/Sodium carbonate
decahydrate
Page 10 of 12 X_086_ 31/1/1
β’ FeSO4.7H2O/ Green Vitrol/Ferrous sulphate hepta hydrate
β’ CaSO4 . Β½ H2O/ Calcium Sulphate hemihydrate /POP
(Any two examples ) Β½,Β½