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In acid-base titration react rapidly to neutralise each other. Equivalence point is a point at which the acid and the base (or oxidising agent and reducing agent) have beem added in equivalent quantities. The end point in the point at which the titration stops. since the purpose of the indicator is to stop the titration close to the point at which the acid and base were added in equivalent quantities, it is important that the equivalent point and the end point be as close as must change colour at a `pH` close to that of a solution of the salt of the acid base. Singificantly, the `pH` changes most rapidly near the equivalent point. The exact shape of a titration curve depends on `K_(a)` and `K_(b)` of acid and base. Which of the following curves indicates the titration of a weak diprotic acid by `KOH` of equivalent strength?A. B. C. D. |
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Answer» Correct Answer - A In Fig (a), there are two equivalence point and `pH` changes most repidly at that point, so it is a titration of a weak diprotic acid by a strong base. At the end `pH` is very high and suggest a strong base. Figs. (b), (c) and (d) do not have high, `pH` at the end. So strong base is not possible. Moreover `pH` does not change repidly at equivalence point. |
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