m-amino phenol is a stronger acid …

First draw the resonance structure of both . As we know that is resonance the negative charges goes to the alternate C atoms....so in case of o-amino phenol the NH2 shows +R effect and gives its electrons to the ring and the -ve charges goes to the C atom attached to OH grp and therefore electrons move to OH grp, it increases electron density on OH grp and therefore it is difficult to release H+ ion and hence less acidic While in case of m-amino phenol the the NH2 shows +R and in this case the electrons will not go to the C atom attached to OH grp ...else it will go to the next C atom ( as alternate C atoms will get -ve charge) ...and therefore electron density will not increase on OH grp and it will be easy to release H ion and hence more acidic I also had the same doubt before and i hope you got your doubt solved!