# Question 15d80

May 13, 2017

A method for the determination of chlorine, bromine, and iodine in the form of halides by precipitating them with excess silver nitrate and titrating the excess with a thiocyanate solution.

#### Explanation:

Volhard's method is a method in argentometry where the word "argentum" is Latin for silver. Argentometry is a type of titration involving the silver ion.

Volhard's method was discovered by Jacob Volhard, a German chemist in 1874. It is an indirect titration procedure, used for determining the anions that precipitate with silver.

Here are the steps:

1. Analyte is treated with the measured excess of silver nitrate
2. The unreacted silver ions are titrated with a standard solution of thiocyanate ion using Fe(III) as indicator
3. The first slight excess of thiocyanate ion turns red, FeSCN""^(2+)#

This method is very useful when the solution has to be acidic. However, it is also very time consuming.