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.
BITSAT
Chemistry
Ionic Equilibrium
2020
BITSAT 2020
BITSAT Chemistry Question (2020) — Solution
Options
- A. Ba ( OH )_ 2 ( ~K _ sp =1.1 10^ -4 )
- B. Mg ( OH )_ 2 ( ~K _ sp =3.5 10^ -4 )
- C. Fe ( OH )_ 2 ( ~K _ sp =8.1 10^ -16 )
- D. Ca ( OH )_ 2 ( ~K _ sp =2.1 10^ -5 ) ).
Answer
C. Fe ( OH )_ 2 ( ~K _ sp =8.1 10^ -16 )
Step-by-step solution
pH =8, pOH =6 ; [ OH ^ - ]=10^ -6 M Ionic product of Fe ( OH )_ 2 =0.2 (1 10^ -6 )^ 2 =2 10^ -13 > K _ sp (=8.1 10^ -16 )
Related: Chemistry — Ionic Equilibrium · All PYQ Banks