# Ksp question

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#### Erhatstil

##### Full Member
10+ Year Member
15+ Year Member
Can Ksp be directly related to the initial concentration of a solution?

for example if we know the Ksp of AgI is 16x10^-10, and since AgI-->Ag+ + I-, then [x]=square root of 16x10^-10= 4x10^-5M.

so since AgI--->Ag+ + I- can I add (4x10^-10)+(4x10^-10) and say we started with a concentration of 8x10^-10M of AgI??

thanks

#### sfoksn

##### Full Member
15+ Year Member
AgI is solid Also, notice that the Ksp is very low, which means it didn't dissociate completely, not even close to being dissociated completely.

So you probably can't do that..

Not sure though

#### UCB05

##### Full Member
10+ Year Member
Can Ksp be directly related to the initial concentration of a solution?

for example if we know the Ksp of AgI is 16x10^-10, and since AgI-->Ag+ + I-, then [x]=square root of 16x10^-10= 4x10^-5M.

so since AgI--->Ag+ + I- can I add (4x10^-10)+(4x10^-10) and say we started with a concentration of 8x10^-10M of AgI??

thanks

Not exactly. You got the calculation of x right. 4x10^-5M will be the concentration of Ag+ and I- ions in a saturated solution. This will also be the effective AgI concentration, not (4x10^-5)+(4x10^-5). 8x10^-5 would be the total concentration of ions. If and only if a question stated it is a saturated solution can you say that the initial concentration of solute was 4x10^-5M before dissociation