If I have BTC on an exchange at the time of the fork, will I get my free BTG?
Cryptocurrency exchanges are custodial businesses, which means they control your private keys, not you. A exchange that was holding BTC on your behalf at the time of the snapshot will also receive the corresponding BTG. While they should credit your account with the equal amount of BTG, there is no legal authority that can force them to do so. The Bitcoin Gold home page displays the names and logos of exchanges that are already prepared to credit their users with BTG at the 1:1 ratio. If your exchange is not shown, it would be wise to consult with your exchange for full information on their policy.