The Mercury year is between 1 and 2 days. Has it ever been greater, and will it eventually become "tidally locked" with the Sun?
Mercury is tidally locked; it has a 3:2 resonance with the Sun, where it rotates three times for every two orbits. It is well understood that Mercury is tidally locked, but modern explanations for how it could’ve come to be are currently unsatisfactory (see this publication from Nature https://www.nature.com/articles/nature02609).
It will probably never leave the resonance it is in now in favor of some 1:1 resonance for the simple fact that it’s current state has the negative feedback of being in a potential energy well; to leave it for a different resonance would take some significant outside interaction, and may not be possible (the lack of certainty of whether this could be possible rises from the lack of certainty in how Mercury came to this specific resonance in the first place)