The K sp for bismuth sulphide ( Bi 2 S 3) is 1.08 × 10-73. The solubility of Bi 2 S 3 in mol L -1 at 298 K is

Question

The K sp for bismuth sulphide ( Bi 2 S 3) is 1.08 × 10-73. The solubility of Bi 2 S 3 in mol L -1 at 298 K is (A) 1.0 × 10-15 (B) 2.7 × 10-12 (C) 3.2 × 10-10 (D) 4.2 × 10-8

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/5e3cf75f87396d2c9e505108ab62dcbe-.png" /> k sp =(2 s )2(3 s )3 =4 s 2 × 27( s )3 =108( s )5 ( s )5 =(1.08 × 10-73/108) ⇒ s =10-15

Q. The $K_{s p}$ for bismuth sulphide $(B i_{2} S_{3})$ is $1.08 \times 1 0^{- 73}$ . The solubility of $B i_{2} S_{3}$ in $m o l L^{- 1}$ at $298 K$ is

$1.0 \times 1 0^{- 15}$

$2.7 \times 1 0^{- 12}$

$3.2 \times 1 0^{- 10}$

$4.2 \times 1 0^{- 8}$

$k_{s p} = (2 s)^{2} (3 s)^{3}$
$= 4 s^{2} \times 27 (s)^{3}$
$= 108 (s)^{5}$
$(s)^{5} = \frac{1.08 \times 1 0 ^{- 73}}{108}$
$\Rightarrow s = 1 0^{- 15}$

Q. The Ksp​ for bismuth sulphide (Bi2​S3​) is 1.08×10−73. The solubility of Bi2​S3​ in molL−1 at 298K is

1.0×10−15

2.7×10−12

3.2×10−10

4.2×10−8