Question 4 (30 marks) A seashore sand contains
85%insoluble sand,
12%salt, and
3%water. One thousand, 1000 kg of this mixture is to be extracted so that after drying it will contain only
0.2%salt.
^(B )How many washings with
2000\deg kgbatches of pure water are required to give the desired purity? The sand retains 0.5 kg of water per kg of insoluble sand.
