For the titration of a strong acid with a strong base, the equivalence point at which base completely neutralizes the acid has a pH of 7.0. Select and justify your choice of an indicator that will allow you to visually determine the equivalence point.
Question
For the titration of a strong acid with a strong base, the equivalence point at which base completely neutralizes the acid has a pH of 7.0. Select and justify your choice of an indicator that will allow you to visually determine the equivalence point.
Solution
For the titration of a strong acid with a strong base, the equivalence point is indeed at a pH of 7.0. This is because strong acids and strong bases completely ionize in solution, and at the equivalence point, the number of moles of H+ ions from the acid equals the number of OH- ions from the base, resulting in a neutral solution with a pH of 7.0.
An ideal indicator for this titration would be one that changes color around a pH of 7.0. Phenolphthalein, for example, is not a good choice because it changes color at a pH of 8.2 - 10.0, which is past the equivalence point for this titration.
A better choice would be bromothymol blue, which changes color at a pH range of 6.0 - 7.6. This range straddles the equivalence point pH of 7.0, allowing you to visually determine when the reaction has reached the equivalence point.
Another good choice would be methyl orange, which changes color at a pH range of 3.1 - 4.4. Although this range is below the equivalence point, the sharp color change can still provide a good approximation of when the equivalence point is reached.
In conclusion, for the titration of a strong acid with a strong base, bromothymol blue would be the best choice of indicator due to its color change range closely matching the equivalence point pH of 7.0.
Similar Questions
For the titration of a strong acid with a strong base, which of the following indicators would be most suitable?bromomethyl blue, pH range 6.0–7.6bromocresol green, pH range 3.8–5.4methyl orange, pH range 3.1–4.4methyl red, pH range 4.2–6.3Submit answer
WHICH OF THE FOLLOWING IS USED AS AN INDICATOR IN THE TITRATION OF A WEAK ACID AND A STRONG BASE?
The best indicator for the detection of end point in titration of a weak acid and a strong base is :-Methyl orange (3.1 to 4.4)Methyl red (4.2 to 6.3)Bromothymol blue (6 to 7.6)Phenolphthalein (8.2 to 10)
What is the pH at the equivalence point for the titration between sodium hydroxide and acetic acid?
The commonly used indicators for the titration of the mixture of strong and weak bases against astrong acid are the following exceptA. PhenolphthaleinB. Methyl redC. Alizarin blueD. Methyl orange
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