A solution of NH 4 Cl and NH 3 has pH =8.0. Which of the following hydroxides may be precipitated when this solution is mixed with equal volume of 0.2 M of metal ion.

Question

A solution of NH 4 Cl and NH 3 has pH =8.0. Which of the following hydroxides may be precipitated when this solution is mixed with equal volume of 0.2 M of metal ion. (A) B a(O H)2(Ks p=1.1 × 10-4) (B) M g(O H)2(Ks p=3.5 × 10-4) (C) F e(O H)2(Ks p=8.1 × 10-16) (D) Ca ( OH )2(Ks p=2.1 × 10-5)

Tardigrade Admin · Accepted Answer

pH =8, pOH =6 ;[ OH -]=10-6 M Ionic product of Fe ( OH )2=0.2 ×(1 × 10-6)2 =2 × 10-13>Ks p(=8.1 × 10-16)

Q. A solution of $N H_{4} Cl$ and $N H_{3}$ has $p H = 8.0$ . Which of the following hydroxides may be precipitated when this solution is mixed with equal volume of $0.2 M$ of metal ion.

$B a (O H)_{2} (K_{s p} = 1.1 \times 1 0^{- 4})$

$M g (O H)_{2} (K_{s p} = 3.5 \times 1 0^{- 4})$

$F e (O H)_{2} (K_{s p} = 8.1 \times 1 0^{- 16})$

$C a (O H)_{2} (K_{s p} = 2.1 \times 1 0^{- 5})$

$p H = 8, pO H = 6; [O H^{-}] = 1 0^{- 6} M$
Ionic product of $F e (O H)_{2} = 0.2 \times (1 \times 1 0^{- 6})^{2}$
$= 2 \times 1 0^{- 13} > K_{s p} (= 8.1 \times 1 0^{- 16})$

Q. A solution of NH4​Cl and NH3​ has pH=8.0. Which of the following hydroxides may be precipitated when this solution is mixed with equal volume of 0.2M of metal ion.

Ba(OH)2​(Ksp​=1.1×10−4)

Mg(OH)2​(Ksp​=3.5×10−4)

Fe(OH)2​(Ksp​=8.1×10−16)

Ca(OH)2​(Ksp​=2.1×10−5)