Answer to Question #210594 in General Chemistry for thi@

Question

 The composition of PBS is 0.137M NaCl, 0.012M Phosphate, 0.0027M KCl, pH 7.4. Below is the protocol to make 1 liter of 10x concentrate PBS.

 Combine the following:

Answer 1

The reaction given:

H₂PO₄^-_(aq) ⇆ H⁺_(aq) + HPO₄^2-_( aq)

Here, H₂PO₄^- ion serves as a proton donor, while HPO₄^2- ion is a proton acceptor. In a PBS solution, Na₂HPO₄ dissociates into Na⁺ and HPO₄^2-. As a result, this molecule serves as a proton acceptor. In contrast, KH₂PO₄ dissociates into K⁺ and H₂PO₄^-. As H₂PO₄^- is a proton donor, KH₂PO₄ serves as a proton donor in a PBS solution.