I've just diluted a 95% rubbing alcohol bottle with water to bring it down to 70%. However, the bottle got noticeably warmer after I did so. I've searched online and I couldn't find any exothermic reaction that happens when alcohol is mixed with water. I did use mineral water by mistake to do so, so my best guess is that alcohol reacted with... one of the salts in the water... maybe?! (I have no idea)
Why did this happen?