Zero and first conditional

Used to describe something that is always true.

It's always true. Under such conditions this is what always happens.

If you leave ice in the sun, it melts.

Even if you change the order of the parts, the rule remains the same.

Ice melts if you leave it in the sun.

When I go to bed, I turn off all the lights in the room.

Used to talk about possible future events

If I see John in the future, I will tell him something.

If you don't help me, I'll fail this task.

And even if you change them places, the rule still remains the same.

I'll fail this task if you don't help me.

Not correct!

I'll call you if I will have time.

Correct!

I'll call you if I have time.

When

Unless

As soon as

Until

Before

After

In case

Can

If you don't follow the rules, you can have problems.

May

If you don't follow the rules, you may get into trouble.

Be going to

If you do that, you are going to get into trouble.

Impertaive

If you see him, tell him the news.

So technically you are saying: "You will pass the exam if you don't study hard". Not too logical, isn't it?