You won't catch the train if you don't/won't leave in time [closed]

Solution 1:

As implied in the comments, the specific meaning of the two are slightly different (albeit both grammatically correct). It helps to break down the contractions.

You will not catch the train if you do not leave on time

This phrase is neutral in its blame: not catching the train will happen if you, for whatever reason, do not leave on time.

You will not catch the train if you will not leave on time

This places blame more directly on addressee: 'will not' implies that the addressee plays a causal role in themselves being late for the train, as if they refuse to leave at the correct time.

Solution 2:

You won't (will not) catch the train if: a. you don't (do not) leave in time. This allows for several circumstances to be the cause of the delay, and the warning serves generically to bring attention to the need for timeliness. b. you won't (will not) leave in time. This specifies that the person has control over their situation, and if they choose not to, then they will suffer the explained consequence.