How does back titration work?

A back titration is a titration method where the concentration of an analyte is determined by reacting it with a known amount of excess reagent. The second titration’s result shows how much of the excess reagent was used in the first titration, thus allowing the original analyte’s concentration to be calculated.

How do you do iodometric titration?

Add to Erlenmeyer flask 50 mL of demineralized water, 10 mL of sulfuric acid solution, 10-15 mLs of potassium iodide solution, and two drops ammonium molybdate solution. Titrate with 0.1 N sodium thiosulfate to faint yellow or straw color. Swirl or stir gently during titration to minimize iodine loss.

What is the difference between Iodometry and Iodimetry titration?

Iodometry is the quantitative analysis of a solution of an oxidizing agent by adding an iodide that reacts to form iodine whereas iodimetry is a volumetric analysis involving either titration with a standardized solution of iodine.

What is iodometric method principle?

Estimation of Iodine Content in Iodised Salt by Iodometric Titration. Principle. The principle is that iodine is liberated by adding sulphuric acid to a solution of iodised salt. Potassium iodide solution is added to keep the iodine in the dissolved state.

Why iodometric titrations are done quickly?

In these cases the titration of the liberated iodine must be completed quickly in order to eliminate undue exposure to the atmosphere since an acid medium constitutes an optimum condition for atmospheric oxidation of the excess iodide ion.

Why iodometric titrations are done in dark?

The reaction mixture should be kept in the dark before titration because light accelerates a side reaction in which iodide ions are oxidized to iodine by atmospheric oxygen.

Why KI is added in iodometric titration?

Excess KI is added to help solubilise the free iodine, which is quite insoluble in pure water under normal conditions.

Why excess KI solution is used in iodometric titration?

In an iodometric titration, a starch solution is used as an indicator since itcan absorb the I2 that is released. This absorption will cause the solution to change its colour from light yellow to a dark blue colour when titrated with standardised thiosulfate solution. This indicates the end point of the titration.

Why back titration is more accurate than the direct titration?

The main difference between back titration and direct titration is that a back titration determines the concentration of the unknown by determining the remaining amount of the compound with a known concentration whereas a direct titration directly measures the concentration of the unknown compound.

What is the difference between a titration and a back titration?

In a direct titration, you add a standard titrant to the analyte until you reach the end point. In a back titration, you add an excess of standard titrant to the analyte, and then you titrate the excess titrant to determine how much is in excess.