If 0.50 L of a buffer containing 1.0 mol H₂PO₄^- and 1.0 mol HPO₄²^- is diluted to a volume of 5.0 L,the pH A) increases by 1. B) decreases by 1. C) increases by 10. D) decreases by 10. E) remains unchanged.

Question

Quizplus · Accepted Answer

A buffer resists changes in pH when it is diluted or when small amounts of acid or base are added to it. This is because a buffer contains a weak acid and its conjugate base (or a weak base and its conjugate acid) that can react with any added acid or base and maintain a relatively constant pH. In this case, the buffer contains both H₂PO₄F1F1F1S1^F1F1F10 and HPO₄²F1F1F1S1^F1F1F10, which are a weak acid and its conjugate base, respectively. When the buffer is diluted, the concentrations of the weak acid and its conjugate base decrease proportionally, but their ratio remains the same. This means that the buffer capacity is still present and can resist changes in pH. Therefore, the pH remains unchanged.

If 050 L of a Buffer Containing 1