Question

Recently the one group of students from ‘Engineers without Border’ (EWB) went to Barundi to provide safe drinking water and found that drinking water well will be the best option. The World Health Organization standard for Al (Al3+) is 7.0 mg/L. The soil analysis of the area showed that presence of 0.3408% Aluminum Sulfate [Al2(SO4)3] in soil and the group decided to go against the water from well. The Solubility product of Aluminum Sulfate is 1.3 X 10-39. Evaluate the decision taken by the EWB group.

Answer 1

The World Health Organization standard for Al (Al3+) is 7.0 mg/L.(drinking water).

the soil analysis of the area showed that presence of 0.3408% Aluminum Sulfate [Al2(SO4)3] in soil .

0.3408/342 =0.00099 moles.

but aluminium is 2 moles per sulfate 3 moles. 2: 3 ratio.

aluminium(molar mass 26.9) contains how many grams

=0.00099*26.9

=0.026 g or 2.6 g of aluminium presented. so no problem for usage.

only aluminium required as per WHO 7 mg

So  2.6 g of aluminium

the Solubility product of Aluminum Sulfate (342 molar mass) is 1.3 X 10-39.

as per the Al2 (SO4)3 Al ³⁺ + SO₄^3-

solubility product=(1.3 x 10^-39) *(1.3 x 10^-39)

=3.9x10^-39