The technique used for purification of steam volatile water immiscible substance is:

The technique used for the purification of steam volatile, water immiscible substances is called Steam Distillation. Here are the steps involved in this process:

1. The impure substance is placed in a distillation flask. Steam is passed through the flask.

2. The substance vaporizes due to the steam. The temperature is kept just above the boiling point of the substance, but below the boiling point of water.

3. The vaporized substance is then passed through a condenser. The condenser cools the vapor, turning it back into a liquid.

4. The purified substance is collected in a separate container. Since it is immiscible with water, it can be easily separated.

5. The remaining impurities are left behind in the distillation flask.

This method is particularly useful for substances that would decompose at their boiling points under normal atmospheric pressure. By using steam, the boiling point of the substance is effectively lowered, allowing it to vaporize at a lower temperature.