The problem with this question is that there have been several hundred editions of Jane Eyre by Charlotte Brontë since it was first published in 1847. The pagination of these editions varies, and so if I told you on what page these events occurred in the edition I have, there is no guarantee that your edition would have the same information on the same page numbers. There are two ways we can work with this issue.
First, you can download a copy of the novel as an etext from Project Gutenberg:
Since this can be downloaded into your word processing program, you can then use the search function of your word processor to find specific references.
Next, you can read through Chapters 26 and 27, in which Jane and the readers of the novel discover Rochester's past. Although page numbers vary with editions, most editions retain the original chapter numbers and divisions.