Question

In aqueous solution of Al2(SO4)3 concentration of Al+3 is 1.8 M then what is the concentration of SO4–2 ?​

Answer 1

The concentration of Al2(SO4)3 in solution will be 0.073 M . So, you're dealing with an aluminium sulfate solution. In aqueous solution, the compound will dissociate into aluminium cations and sulfate anions. Notice the 1 mole of aluminium sulfate produces 2 moles of aluminium cations and 3 moles of sulfate anions

Answer 2

Given:

Write the equation for aluminum sulfate's dissociation

$\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3} \rightleftharpoons 2 \mathrm{Al}^{3+}+3 \mathrm{SO}_{4}^{2-}$

the 1 mole of aluminum sulfate produces  2  moles of aluminum cations and  3

moles of sulfate anions.

$=\frac{1}{2} \times 1.8$

=0.9

Hence the answer is 0.9M