You are provided with 1.0M solutions of NaCl, (NH_{4}) 2 SO 4 , MgSO4 and K_{3}P*O_{4} In which of these solutions would a protein be expected to be lest soluble?

(1) NaCl

(2) (N*H_{4}) 2 SO 4

(3) MgSO4

(4) K_{3}PO_{4}

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The solubility of a protein in a salt solution is influenced by the salting-out effect, which depends on the ionic strength of the solution. The higher the ionic strength, the more the protein tends to precipitate out of solution.

Understanding Ionic Strength:

Ionic strength (I) is given by the formula:

Conclusion:

Since proteins are least soluble in solutions with the highest ionic strength, the correct answer is:

(4) K₃PO₄ (Potassium phosphate)