Titration

Question 1

What are the types of titration?

Answer 1

Mohr’s, Volhard’s, and Fajan’s

Question 2

How does Mohr’s method of titration work?

Answer 2

Mohr’s method uses silver nitrate as the titrant and potassium chromate as the indicator. The indicator starts yellow and reacts with excess silver to turn reddish brown

Question 3

Pros and Cons of Mohr’s method

Answer 3

Pros:
* Simpler
Cons:
* Does not work with acidic conditions
* Colour change is less obvious

Question 4

How does Volhard’s method of titration work?

Answer 4

Volhard’s method of titration is a form of back titration. It uses a known excess of silver ions to precipitate all of the chlorine ions, then Fe(III) ions are added as an idicator and titrated with SCN ions till a stable blood red complex is formed.

Question 5

What are the pros and cons of Volhard’s method?

Answer 5

Pros:
* Works in acidic conditions
* Obvious colour change
Cons:
* More complex

Question 6

How is the burette prepared for titration?

Answer 6

The burette is first washed with water, then with the titrant, before being filled with the titrant

Question 7

How is the pipette prepared for titration?

Answer 7

The pipette is rinsed multiple times with the solution to be transferred.

Question 8

How is the conical flask prepared for titration?

Answer 8

The conical flask is rinsed by water and not rinsed with any solutions

Question 9

Mohr’s method summary

Answer 9

measures when all the chlorine has reacted

Question 10

Volhards method summary

Answer 10

reacts all the chlorine with silver and measure the change in silver moles