To consider the purchase of property for public purposes, the sale of property at competitive bidding, or the sale or other disposition of unneeded, obsolete, or unfit-for-use property in accordance with section 505.10 of the Revised Code, if premature disclosure of information would give an unfair competitive or bargaining advantage to a person whose personal, private interest is adverse to the general public interest. No member of a public body shall use division (G)(2) of this section as a subterfuge for providing covert information to prospective buyers or sellers. A purchase or sale of public property is void if the seller or buyer of the public property has received covert information from a member of a public body that has not been disclosed to the general public in sufficient time for other prospective buyers and sellers to prepare and submit offers.