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:

The Ksp of the magnesium phosphate is 2.53x10⁻¹⁰

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:

$n_{magnesium-phosphate} =\frac{1.24}{262.775} =4.72x10^{-3} moles$

The molarity is:

$M=\frac{4.72x10^{-3} }{1} =4.72x10^{-3} M$

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

$K_{s} =(3*4.72x10^{-3} )^{3} (2*4.72x10^{-3} )^{2} =2.53x10^{-10}$

Answer 2

Answer: 2.52 x 10^(-10)