In order to see the passwords used by your Mac, navigate to the applications folder and open other and then Keychain Access. Once open, select System inside the Keychain box and look for your network, double click the chosen network and tick the show password box. A dialogue box will then pop up and ask you to confirm you password and then may ask for an administrators details, complete each respectively and the password will then be shown.
Accessing WiFi password history – Mac
