Single Choice

The best indicator for the detection of endpoint in the titration of a weak acid and a strong base is:

Amethyl orange (3 to 4)
Bmethyl red (5 to 6)
Cbromothymol blue (6 to 7.5)
Dphenolphthalein (8 to 9.6)
Correct Answer

Solution

Phenolphthalein is an indicator used for titrations of a weak acid and strong base, and itself is a weak acid. The weak acid is colourless and its ion is bright pink. It distinguishes the pH range from 8 to 9.6. Adding extra hydrogen ions shifts the position of equilibrium to the left, and turns the indicator colourless. Adding hydroxide ions removes the hydrogen ions from the equilibrium which shifts to the right to replace them - turning the indicator pink.

Methyl orange, Methyl red are used for the titration of strong acid and strong base or strong acid and weak base while Bromothymol blue is used for weak acid and weak base titration indicator.

SIMILAR QUESTIONS

Acids, Bases and Salts

In the titration of $$NaOH$$ and $$HCl$$, which of the following indicator will be used?

Acids, Bases and Salts

In the titration of strong acid and weak base, the indicator used is:

Acids, Bases and Salts

Two solutions X and Y are tested with universal indicator. Solution X turns orange whereas solution Y turns red. Which of the solutions is a stronger acid?

Acids, Bases and Salts

Which of the following indicator is most suitable for titration of $$HB$$ with strong base

Acids, Bases and Salts

A solution containing $$Fe^{2+}$$ ions is titrated with $$KMnO_{4}$$ solution. Indicator used will be:

Acids, Bases and Salts

0.1 N solution of $${ Na }_{ 2 }{ CO }_{ 3 }$$ is titrated with 0.1 N HCl, best indicator is :

Acids, Bases and Salts

A solution containing $$Na_{2}CO_{3}$$ and $$NaOH$$ requires $$300\ mL$$ of $$0.1\ N\ HCl$$ using phenolphthalein as an indicator. Methyl orange is then added to the above-titrated solution when a further $$25\ mL$$ of $$0.2\ N\ HCl$$ is required. The amount of $$NaOH$$ present in the original solution is:

Acids, Bases and Salts

A solution containing $$Fe^{2+}$$ ions is titrated with $$KMnO_{4}$$ solution. Indicator used will be:

Acids, Bases and Salts

The indicator used in iodometric titrations is:.

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