Experience the power of community-driven knowledge on IDNLearn.com. Discover thorough and trustworthy answers from our community of knowledgeable professionals, tailored to meet your specific needs.

A buffer solution is prepared by adding [tex]NaH_2PO_4[/tex] to a solution of [tex]H_3PO_4[/tex] (phosphoric acid).

[tex]H_3PO_4(aq) \rightleftharpoons H^{+}(aq) + H_2PO_4^{-}(aq)[/tex]

What happens if NaOH is added?

A. Shifts to products
B. Remains the same
C. Shifts to reactants


Sagot :

When NaOH is added to the buffer solution containing [tex]\(H_3PO_4\)[/tex] and [tex]\(NaH_2PO_4\)[/tex], it will affect the equilibrium of the reaction:

[tex]\[ H_3PO_4(aq) \rightleftharpoons H^+(aq) + H_2PO_4^-(aq) \][/tex]

Here’s a detailed, step-by-step explanation of what happens:

1. Initial Conditions: We start with a buffer solution made from [tex]\(H_3PO_4\)[/tex] and [tex]\(NaH_2PO_4\)[/tex]. The equilibrium in this solution follows the reaction:

[tex]\[ H_3PO_4(aq) \rightleftharpoons H^+(aq) + H_2PO_4^-(aq) \][/tex]

2. Addition of NaOH: Sodium hydroxide ([tex]\(NaOH\)[/tex]) is a strong base and dissociates completely in water to give [tex]\(Na^+\)[/tex] and [tex]\(OH^-\)[/tex] ions.

3. Reaction of [tex]\(OH^-\)[/tex] with [tex]\(H^+\)[/tex]: The hydroxide ions ([tex]\(OH^-\)[/tex]) from [tex]\(NaOH\)[/tex] will react with the hydrogen ions ([tex]\(H^+\)[/tex]) in the solution to form water:

[tex]\[ OH^-(aq) + H^+(aq) \rightarrow H_2O(l) \][/tex]

4. Decrease in [tex]\(H^+\)[/tex] Concentration: As [tex]\(OH^-\)[/tex] ions react with [tex]\(H^+\)[/tex] ions, the concentration of [tex]\(H^+\)[/tex] ions in the solution decreases.

5. Shift in Equilibrium: According to Le Chatelier’s principle, any change in the concentration of reactants or products in a chemical equilibrium will cause the equilibrium to shift in a direction that counteracts the change. In this case, the decrease in [tex]\(H^+\)[/tex] ions will cause the equilibrium to shift to the right (towards the products) to produce more [tex]\(H^+\)[/tex] ions.

[tex]\[ H_3PO_4(aq) \rightleftharpoons H^+(aq) + H_2PO_4^-(aq) \][/tex]

By shifting to the right, more [tex]\(H_3PO_4\)[/tex] will dissociate to make up for the loss of [tex]\(H^+\)[/tex] ions. Therefore, the equilibrium will shift towards the products.

Based on this analysis, when NaOH is added to the buffer solution, the equilibrium shifts to products.
We are delighted to have you as part of our community. Keep asking, answering, and sharing your insights. Together, we can create a valuable knowledge resource. For clear and precise answers, choose IDNLearn.com. Thanks for stopping by, and come back soon for more valuable insights.