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Grade 11Physical Chemistry

solubility product of M(OH)2 If its saturated solution has PH 10 at 25 celsius?

Profile image of priya
8 Years agoGrade 11
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1 Answer

Profile image of Arun
8 Years ago

The chemical equation:

Mg(OH)2 ⇌ Mg2+ + 2OH¯

2) The Ksp expression:

Ksp = [Mg2+] [OH¯]2

3) Use the pH to get the pOH:

14.00 - 10.17 = 3.83

4) Use the pOH to get the [OH¯]:

[OH¯] = 10¯pOH = 10¯3.83 = 1.479 x 10¯4M

5) From the chemical equation, we note that the [Mg2+] is half the value of the [OH¯], therefore:

[Mg2+] = 1.479 x 10¯4 M divided by 2 = 7.395 x 10¯5 M

6) We now have the necessary values to put into the Ksp expression:

Ksp = (7.395 x 10¯5) (1.479 x 10¯4)2

Ksp = 1.62 x 10¯12