what is hofmann rule. please explain it

Hofmann rule is an empirical rule used to predict regioselectivityof1,2-eliminationreactions occurring viaE1cB mechanism. It states that, in a regioselectiveE1cB reaction, the major product is the less stablealkene, i.e., the alkene with the less highly substituted double bond. For example seeHofmann elimination.

When aprimary aminebearing one or morebeta hydrogensis treated with methyl iodide, followed by aqueous silver oxide, followed by heat, the primary amine is converted to analkene. This reaction is known as Hofmann elimination, not to be confused withHofmann rearrangement.
Check the fig.