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H3PO4 (aq) + H2O (l) ⇔ H2PO4- (aq) + H3O+ (aq) Ka = 7.1 x 10-3

A buffer was prepared using 0.00650 M H3PO4 and 0.0125 M NaH2PO4. Calculate the pH of the buffer solution.

Respuesta :

ardni313

The pH of the buffer solution : 2.433

Further explanation

A buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.  

The buffer solution can be acidic or basic  

Acid buffer solution consists of weak acids (H₃PO₄) and their salts(NaH₂PO₄)  

[tex]\tt [H^+]=Ka\times\dfrac{[\:weak\:acid]}{[salt]\times valence}[/tex]

valence according to the amount of salt anion  

[H₃PO₄]=0.00650 M

[NaH₂PO₄]=0.0125 M

[tex]\tt [H^+]=7.1.10^{-3}\dfrac{0.0065}{0.0125}\\\\(H^+]=3.692.10^{-3}\\\\pH=-log[H^+]\\\\pH=3-log3.692\\\\pH=2.433[/tex]

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