Statement 1: When 10 ml of 0.5 M - NaHCO₃ solution is titrated with 0.25 M - HCl solution using phenolphthalein indicator, 20 ml of acid solution is consumed at the end point.
Statement 2: End point cannot be detected when NaHCO₃ solution is titrated with HCl solution using phenolphthalein indicator.

Question

Statement 1: When 10 ml of 0.5 M - NaHCO₃ solution is titrated with 0.25 M - HCl solution using phenolphthalein indicator, 20 ml of acid solution is consumed at the end point.

Statement 2: End point cannot be detected when NaHCO₃ solution is titrated with HCl solution using phenolphthalein indicator.

TestHub · Accepted Answer

NaHCO₃ is amphiprotic and its solution (pH ~ 8.3) lies below the phenolphthalein transition range (8.3-10), so the solution is already colourless in phenolphthalein and no sharp end point appears - II is correct, and consequently the claimed 20 ml consumption at a phenolphthalein end point is wrong - I is incorrect. Hence (d).

Chemistry - Redox Reactions Question with Solution | TestHub

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