No member of any zoning commission or board and no member of any zoning board of appeals or of any municipal agency exercising the powers of any zoning commission or board of appeals, whether existing under the general statutes or under any special act, shall appear for or represent any person, firm, corporation or other entity in any matter pending before the planning or zoning commission or board or said board of appeals or any agency exercising the powers of any such commission or board in the same municipality, whether or not he is a member of the board or commission hearing such matter. No member of any zoning commission or board and no member of any zoning board of appeals shall participate in the hearing or decision of the board or commission of which he is a member upon any matter in which he is directly or indirectly interested in a personal or financial sense. In the event of such disqualification, such fact shall be entered on the records of the commission or board and, unless otherwise provided by special act, any municipality may provide by ordinance that an elector may be chosen, in a manner specified in the ordinance, to act as a member of such commission or board in the hearing and determination of such matter, except that replacement shall first be made from alternate members pursuant to the provisions of sections 8-1b and 8-5a.