Can Ifile divorce by publication if I don’t know what state that my husband is in?

The concept of divorce by publication is made for the very circumstance that you have here - a spouse's whereabouts are unknown. In any legal proceeding the concept of "notice" is critical. Legal action should not be taken against someone without giving them the right to appear and explain their side of things (in this case to answer the divorce complaint). Therefore, even if a spouse can't be located they still must be notified of the divorce action before it can proceed. This is what is accomplished in a "divorce by publication".

In brief this is the way it typically works. You as the filing spouse (i.e. Petitioner) must make a diligent effort to find your missing spouse (i.e. Respondent).  You will have to present proof to a court that you made a true effort to locate him. To prove your best efforts you will have to show the court that you checked with family/friends, voting records, the phone book, DMV, and any other source that would likely lead to uncovering his current whereabouts.  Once you have demonstrated to the the court's satisfaction that you have made a thorough search, you will be allowed to serve your spouse by publishing notice in a newspaper (as opposed to the more usual method of personal service).  The court will instruct as to which paper should be used (typically one in the area of your spouse's last known address).  

Generally, in most states, the Respondent has 30-60 days to file a reply after the first day of publication. If they fail to respond within that time, the Petitioner files a request to enter a default dissolution of marriage. And it generally grants it upon the terms requested by the Petitioner (although the Respondent is given a certain time limit in which they can appeal).