Separating a mixture containing different substances like salt, sand, and Sulphur relies on their unique physical properties, such as solubility in different solvents and magnetic properties. While the question mentions "iron," the specific separation method described below, based on the provided reference, focuses on separating salt, sand, and Sulphur using water and carbon disulphide. Separating iron from the mixture would typically involve using a magnet as a first step.
Here is a step-by-step process for separating salt, sand, and Sulphur from a mixture using techniques based on solubility:
Steps for Separating Salt, Sand, and Sulphur
This procedure leverages the fact that salt is soluble in water, Sulphur is soluble in carbon disulphide, and sand is largely insoluble in both.
Step 1: Add Water to the Mixture
- Action: Add water to the mixture of salt, sand, and Sulphur.
- Explanation: Salt (sodium chloride) is soluble in water, meaning it will dissolve and form a salt solution. Sand and Sulphur are insoluble in water and will remain as solid particles.
Step 2: Filter the Mixture
- Action: Filter the mixture using filter paper and a funnel.
- Explanation: The liquid portion, which is the salt solution (filtrate), passes through the filter paper. The solid particles that do not dissolve, consisting of Sulphur and sand, are left behind on the filter paper as the residue.
Step 3: Evaporate the Filtrate
- Action: Heat the filtrate (the salt solution) gently, typically in an evaporating dish.
- Explanation: As the salt solution is heated, the water will vapourize and turn into steam, leaving behind the solid salt crystals.
Step 4: Add Carbon Disulphide to the Residue
- Action: Take the residue (which contains Sulphur and sand) and add carbon disulphide to it.
- Explanation: Sulphur is soluble in carbon disulphide, so it will dissolve and form a solution. Sand is insoluble in carbon disulphide and will remain as solid particles.
Step 5: Filter this Solution
- Action: Filter the mixture from Step 4.
- Explanation: The liquid portion, which is the Sulphur dissolved in carbon disulphide, passes through the filter paper. The solid sand particles are left behind on the filter paper.
Note: To recover solid Sulphur, the carbon disulphide solution obtained in Step 5 would typically be evaporated carefully in a fume hood due to the flammability and toxicity of carbon disulphide, but this step is not explicitly detailed in the provided reference.
Component Properties Affecting Separation
Understanding the properties of the components is key to designing the separation method.
| Component | Solubility in Water | Solubility in Carbon Disulphide | Other Relevant Properties |
|---|---|---|---|
| Salt | Soluble | Insoluble | Crystalline solid |
| Sand | Insoluble | Insoluble | Solid particles |
| Sulphur | Insoluble | Soluble | Yellow solid |
| Iron | Insoluble | Insoluble | Magnetic (typically) |
Considerations for Separating Iron
As mentioned earlier, the procedure described using water and carbon disulphide is effective for separating salt, sand, and Sulphur. If iron filings were present in the original mixture, they could be separated before adding any solvents. Iron is magnetic, so a simple method would be to pass a magnet over the dry mixture; the iron particles would be attracted to the magnet and removed. This magnetic separation step is not part of the solvent-based method for salt, sand, and Sulphur.
