1. Do I need to put a comma between two imperative sentences?

Ex. Take the water, and drink it when you are thristy.

2. If yes, then are imperative sentences treated as independent sentences?

3. How does the comma rules apply in the following case?

Case: Wear a red hat so I know it's you.

Do I need a comma before "so"?

Thanks in advance.
1-- No; the comma is incorrect.

2-- Probably not; the understood subject 'you' is only implied once.
3-- No comma.