Question

A completely exhausted zeolite softener required 120 litres of NaCl solution . How many litres of water having hardness 500 pm can be softened by zeolite .

Answer 1

Answer:

The total amount of NaCl required for the softening process is

120 litres*100 mg/lit=12000mg

$CaCl_{2} +Na_{2} Ze--->2NaCl+CaZe$

$1CaCl_{2} --->2NaCl$

$1CaCl_{2} ---->1CaCO_{3}$

Hence $1CaCO_{3} --->2NaCl$

100 mg of $CaCO_{3} =2*58.5 mg of NaCl$

2*58.5 mg of Nacl=$100 mg of CaCO_{3}$

12000 mg of NaCl=12000*100/2*58.5 mg of $CaCO_{3}$

The hardness of yhe water sample is 500 ppm

Then the volume of water required for 12000*100/2*58.5 mg of CaCO3 is

=12000*100/2*58.5*500 litres

=17.55litrs