Please refer to the following blog post http://www.ieltsexamstips.com/2014/02/conditional-statements-in-ielts-exam.html
Type 1 or First Conditionals show possible situations. The if- clause uses the simple present form of the verb while the main clause uses the future simple (will) and certain modals like can, might, and should.
- If she comes home, we will cook dinner.
- If we hurry, we might catch the 8pm bus.
The Type 2 Conditional refers to something unreal or for situations that are imagines. This type of conditional shows that the action is less probable. The if-clause uses the simple past while the main clause uses would, could and might.
- If I ate too much cake, I would get fat.
- If she won a million pesos, she might buy a new house for her family.