Describe 3 everyday situations in which it would be useful to identify unknown substances and explain how you would identify these substances

Here are three everyday situations which it would be useful to identify unknown substances:
1. When you have two clear substances with no labels yet you are not sure which substance is water and which one is not and not knowing what this unknown chemical might do.
2. A stain on your clothes
3. When you are not feeling well and your sense of taste is not functioning well.
The ways that these can be identified is first, start by the appearance, for example the state, color, texture, etc. And secondly, use your sense of smell. This sense is also helpful in identifying whether the substance is something strong or not.

The air is going to come out because of the low pressure.