Question

the value of ksp for pbcl2 is 1.6. what is the lowest concentration of Cl- that would be needed to begin precipitation of PbCl2 in 0.010 M Pb(NO3)2

Answer 1

Answer:

The minimum concentration of Cl⁻ that produces precipitation is 12.6M

Explanation:

The Ksp of PbCl₂ is expressed as:

PbCl₂(s) → Pb²⁺(aq) + 2Cl⁻(aq)

The Ksp is:

Ksp = 1.6 = [Pb²⁺] [Cl⁻]²

When Ksp = [Pb²⁺] [Cl⁻]² the solution begind precipiration.

A 0.010M Pb(NO₃)₂ is 0.010M Pb²⁺, thus:

1.6 = [0.010M] [Cl⁻]²

160 = [Cl⁻]²

12.6M =  [Cl⁻]

The minimum concentration of Cl⁻ that produces precipitation is 12.6M