Chemistry Experiment: Mohr's Salt Preparation

What is Mohr's salt chemically known as?

Which of the following is a component of Mohr's salt?

What is the color of the solid that Mohr's salt crystallizes as?

Mohr's salt is prepared by dissolving an equimolar mixture of hydrated ferrous sulphate and __________ in acidified water.

What is the chemical equation for the preparation of Mohr's salt?

Mohr's salt is used as an oxidizing agent.

List one piece of apparatus used in the experiment to prepare Mohr's salt.

How much ferrous sulphate is weighed accurately for the experiment?

Experiment No. 8: Preparation of Ferrous Ammonium Sulphate

The aim is to prepare a pure sample of ferrous ammonium sulphate, known as Mohr's salt.
Mohr's salt is a significant laboratory reagent, utilized mainly as a reducing agent.
Chemically, Mohr's salt is represented as ferrous ammonium sulphate (FAS), specifically as FeSO₄.(NH₄)₂SO₄ · 6H₂O.
The preparation involves dissolving an equimolar mixture of hydrated ferrous sulphate (FeSO₄·7H₂O) and ammonium sulphate ((NH₄)₂SO₄) in acidified water.
The resulting compound crystallizes as a pale green solid.

Chemical Equation

The reaction is represented by the equation:
- FeSO₄·7H₂O + (NH₄)₂SO₄ → FeSO₄.(NH₄)₂SO₄ · 6H₂O + H₂O
Molar masses of the compounds involved:
- FeSO₄·7H₂O: 278 g/mol
- (NH₄)₂SO₄: 132 g/mol
- FeSO₄.(NH₄)₂SO₄ · 6H₂O: 392 g/mol

Apparatus Required

Necessary equipment includes:
- China dish
- Beakers
- Funnel
- Glass rod
- Tripod stand
- Wire gauze
- Pair of tongs

Chemicals Required

The primary chemicals for the experiment are:
- Ammonium sulphate
- Ferrous sulphate
- Dilute sulphuric acid

Procedure Highlights

Accurately weigh 3.5g of ferrous sulphate and 1.5g of ammonium sulphate.
Transfer the weighed compounds into a 100 mL beaker.
Add approximately 2-3 mL of water to facilitate the dissolution process.

This quiz focuses on the preparation of ferrous ammonium sulphate, commonly known as Mohr's salt. It covers the chemical reaction involved, the apparatus required, and the molar masses of the compounds. Test your knowledge on this important laboratory reagent and its preparation process.