Ksp for Al(OH)3 is 8.5 × 10-32. What is its solubility in moles/litre?

Question

Ksp for Al(OH)3 is 8.5 × 10-32. What is its solubility in moles/litre? (A) 7.5 × 10-8 (B) 7.5 × 10-7 (C) 1.5 × 10-8 (D) 1.5 × 10-7

Tardigrade Admin · Accepted Answer

Al (OH)3 → underset textSAl3+ + underset text3S3OH- Ksp = (S)(3S)2 = 27 S4 27S4 = 8.5 × 10-32 S=√[4]8.5× 10-32 /27 =(0.31 × 10-32)1/4 =0.749 × 10-8 = 7.49 × 10-7 moles /litre.

Q. $K_{s p}$ for $A l (O H)_{3}$ is $8.5 \times 1 0^{- 32}$ . What is its solubility in moles/litre?

$7.5 \times 1 0^{- 8}$

$7.5 \times 1 0^{- 7}$

$1.5 \times 1 0^{- 8}$

$1.5 \times 1 0^{- 7}$

$A l (O H)_{3} \to S A l^{3} + + 3S 3 O H^{-}$
$K_{s p} = (S) (3 S)^{2} = 27 S^{4}$
$27 S^{4} = 8.5 \times 1 0^{- 32}$
$S = 4 8.5 \times 1 0^{- 32} /27$
$= (0.31 \times 1 0^{- 32})^{1/4}$
$= 0.749 \times 1 0^{- 8}$
$= 7.49 \times 1 0^{- 7}$ moles /litre.

Q. Ksp​ for Al(OH)3​ is 8.5×10−32. What is its solubility in moles/litre?

7.5×10−8

7.5×10−7

1.5×10−8

1.5×10−7