Can someone help me with these two questions please? 210 EXPERIMENT 17 Acid Base

Question

Can someone help me with these two questions please? 210 EXPERIMENT 17 Acid Base Equilibria and the Preparation of Buffer Solutions Explain, in your own words, why the pHof the distilled is more sensitive to the addition water of the acid than is the buffer solution: Buffers based on di- or triprotic acids may have multiple pH regions over which they are stable. That is, they exhibit some stability as the pH of solution is equivalent to each of their pKas (pKa1 pKaz, pKa3). you have a di- or triprotic buffer, state below whether you see evidence of this in the form of your If this should be the case. pHcurve. If you do not see evidence of this, explain why

Explanation / Answer

Answer:

Because in distilled water, the effect of added acid/base is unmoderated. Buffers act to resist gross changes in pH.

Explanation:

A buffer contains a weak acid and its conjugate base in appreciable quantities. The pH of the buffer is reasonably close to the pKa of this weak acid.

If we use the buffer equation, we can appreciate this property:

pH=pKa+log10{[A]/[HA]}

At undergraduate level, you should be able to derive this equation. When the concentration of the acid is equal to that of the conjugate base, log10{[A]/[HA]} =log10(1) = 0, so pH=pKa.

In an unbuffered solution, added hydroxide or protium ion is free to express its concentration, and dramatic rises/falls in pH occur. In the buffered solution, added protium ion protonates the base A, but this increase in [HA] is moderated by the logarithmic term.

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