pH of a saturated solution of Ca(OH)
2
is 9. The solubility product (K
sp
) of Ca(OH)
2
is:
- A0.5×10
−15 - B0.25×10
−10 - C0.125×10
−15 - D0.5×10
−10
Solution & Step-by-step Explanation
1. pH=9⟹pOH=14−9=5.
2. [OH
−
]=10
−5
M.
3. For Ca(OH)
2
⇌Ca
2+
+2OH
−
.
If solubility is s, then [Ca
2+
]=s and [OH
−
]=2s.
2s=10
−5
⟹s=0.5×10
−5
M.
4. K
sp
=[Ca
2+
][OH
−
]
2
=s(2s)
2
=4s
3
.
K
sp
=4×(0.5×10
−5
)
3
=4×0.125×10
−15
=0.5×10
−15
2. [OH
−
]=10
−5
M.
3. For Ca(OH)
2
⇌Ca
2+
+2OH
−
.
If solubility is s, then [Ca
2+
]=s and [OH
−
]=2s.
2s=10
−5
⟹s=0.5×10
−5
M.
4. K
sp
=[Ca
2+
][OH
−
]
2
=s(2s)
2
=4s
3
.
K
sp
=4×(0.5×10
−5
)
3
=4×0.125×10
−15
=0.5×10
−15