Hello tutor, I just need the meaning/explanations and examples of numbers 1-2. Thank you!

Status of ultra vires acts or contracts by the corporate ofcers in behalf of the Corporation 1. Ultra vires acts which are illegal per se Null and void 2. Ultra vires acts which are unauthorized or when the corporate officers exceed their authority Unenforceable but they may become enforceable on the basis of {1) express or implied ratication by the corporation (2} doctrine of estoppel or (3) doctrine of apparent authority of the corporate ofcers