1. You wish to purify a compound with a boiling point of 235°C by simple distillation. In order to avoid unwanted decomposition that can occur at such high temperatures, you wish to perform your distillation at a lower temperature. How can you change the conditions of the distillation you will perform to efficiently accomplish this goal?
2. Explain how your change will produce the desired effect?

Explanation:

To purify a substance whose boiling point is so  high that on reaching boiling point , the substance may undergo chemical change , we manage boiling of substance at relatively lower temperature . This can be done at reduced pressure . Boiling point is dependent on the external pressure. If external pressure is reduced , boiling can be managed at a temperature far below actual  boiling point . In this way we can manage the substance to boil at lower temperature thus we can save the substance to undergo chemical change.