Question

6.84 g Al₂(SO₄)₃ is needed to coagulate 2.5 L of As₂S₃ sol completely in 2.0 hrs. The coagulation value of Al₂ (SO₄)₃ is ______.

Options

• 2

• 7

• 8

• 9

Answer 1

6.84 g Al₂(SO₄)₃ is needed to coagulate 2.5 L of As₂S₃ sol completely in 2.0 hrs. The coagulation value of Al₂ (SO₄)₃ is 8.

Explanation:

${\displaystyle 6.84{\text{g Al}}_2{\left({\text{SO}}_4\right)}_3=\frac{6.84}{342}}$ = 0.02 m = 20 mm

2.5 L is coagulated by = 20 mm

1 L is coagulated by = ${\displaystyle \frac{20}{2.5}}$ = 8