Name the technique used to separate a mixture of substances that are soluble in the same solvent.

The technique used to separate a mixture of substances that are soluble in the same solvent is called Chromatography.

Here are the steps involved in this process:

1. Preparation: A stationary phase is prepared. This could be a strip of filter paper or a thin layer of a substance spread on a glass plate.

2. Application of Sample: The mixture to be separated is applied close to one end of the stationary phase.

3. Development: The stationary phase is then placed in a suitable solvent, which acts as the mobile phase. The solvent is absorbed and moves up the stationary phase.

4. Separation: As the solvent moves up, it carries along with it the components of the mixture. Different components move at different rates depending on their solubility in the solvent and their attraction to the stationary phase.

5. Identification: Once the solvent has moved a certain distance, the stationary phase is removed from it. The different components of the mixture will have moved different distances up the stationary phase. These can be identified by their positions or by using locating agents, which react to form coloured compounds.

6. Extraction: The separated components can then be scraped off the stationary phase and extracted for further use or analysis.