The county board of any county may authorize any officer or member of its board to execute and deliver all deeds, grants, conveyances and other instruments in writing, which may become necessary in selling, transferring or conveying any real estate belonging to its county and such deeds, grants, conveyances and other instruments, if made without fraud or collusion, shall be obligatory upon the county to all intents and purposes.
765 ILCS 5/16