Question

1.24 grams of magnesium phosphate tribasic dissolved in 1 l of lemon juice. What is the ksp of the magnesium phosphate tribasic in lemon juice at room temperature?

Answer 1

Answer: 2.52 x 10^(-10)

Answer 2

The Ksp of the magnesium phosphate is 2.53x10⁻¹⁰

Step-by-step explanation:

The molar mass of magnesium phosphate is:

`MMmagnesium-phosphate=(3*MMMg)+(2*MMP)+(8*MMO)=(3*24.305)+(2*30.97)+(8*15.99)=262.775g/mol`

The number of moles is:

`n_(magnesium-phosphate) =(1.24)/(262.775) =4.72x10^(-3) moles`

The molarity is:

`M=(4.72x10^(-3) )/(1) =4.72x10^(-3) M`

The dissociation of magnesium phosphate is:

Mg₃(PO₄)₂ = 3Mg²⁺ + 2PO₄³⁻

The Ks is:

`K_(s) =[Mg^(2+)]^(3)[PO_(4)^(3-) ]^(2) =(3s)^(3) (2s)^(2)`

Where

s = solubility of ions = 4.72x10⁻³

Replacing

`K_(s) =(3*4.72x10^(-3) )^(3) (2*4.72x10^(-3) )^(2) =2.53x10^(-10)`