Question

A city supply of 15000 cubic metres of water per day is treated with a chlorine dosage of 0.5 ppm. For this purpose, the requirement of 25% bleaching powder per day would be

Answer 1

We know that 1 m³ of water has mass of 1,000 kg = 10³ kg = 10³ L.

So a city supply of 15,000 m³/day = 15,000 · 10³ L/day

Amount of Chlorine per day is:

15,000 · 10³ L/day · 0.5 · 10^(-6) kg/L = 7,500 · 10^(-3) kg = 7.5 kg

And because there is 25% bleaching powder:

x · 0.25 = 7.5 kg

x = 7.5 kg : 0.25 = 30 kg

Answer:  30 kg.  

Answer 2

Given:

Supply of water to a city = 15000 cubic metres

Chlorine dosage = 0.54 ppm

25% bleaching powder is used.

Solution:

1 cubic meter water = 1000 kg

And so, 10 cubic liters

For this city,

15,000 cubic meter per day,

So, 15,000 * 10 cubic liters per day

The amount of Chlorine per day,

15,000 * 10 cubic liters per day * 0.5 · 10 ^ ( -6 ) kilogram per liter = 7,500 · 10  ^ ( -3 ) kg

The amount of Chlorine per day = 7.5 kg

As it uses 25% of bleaching powder,

Requirement for 15000 cubic meters,

Bleaching powder required * 0.25 = 7.5 kg

Bleaching powder required = 30 kg

Hence, 30 kg of bleaching powder is required a city supply of 15000 cubic metres of water per day is treated with a chlorine dosage of 0.5 ppm.