Before any petition for submission of such ordinance shall be circulated, an affidavit by or on behalf of its proponents, shall be filed with the city clerk, containing a copy of the proposed ordinance, a statement in not more than two hundred words giving the reasons of said proponents for the adoption of such ordinance, a statement of the intention to secure submission of said ordinance to a vote of the electors by an initiative petition, and the address of the party making such affidavit. The council shall have five days after the filing of such affidavit to send by registered mail to the address given in such affidavit, a statement in not more than two hundred words, of the reasons why such proposed ordinance should not be adopted. These reasons for and against the adoption of the proposed ordinance shall be printed as a part of the individual certificates constituting the petition.