2. If we run out of coffee, we'll be sleepy all day long.
3. Brian will catch up with us if we leave him our contact details.
4. A burglar will run away if we don't call the police.
5. If they cut off too many trees, it will lead to the environmental catastrophe.
6. Не уверена. Насколько мне известно, с tell нету phrasal verbs. По смыслу подошло бы: My dad will tell me a secret if I promise not to tell anyone.
7. If you don't switch of the TV at night, we'll have to pay a lot for electricity.
8. If you don't sit back all day, you will be able to do a lot of useful things. Опять же, не уверена. С ним есть очень много фраз и многие подходят по значению. To sit back - сидеть и ждать чего-то, не прилагая усилий.
Надеюсь, помогла.