By that definition, it can’t be exactly 7 then either. 10^-7 is just an estimate that we’ve agreed works fine. To my knowledge we haven’t really tried to improve this accuracy either?
Comment on Is water an acid or a base?
wolframhydroxide@sh.itjust.works 4 weeks agoWell, yes and no. The pH scale follows the hydrogen ion concentration, but specifically in aqueous media. The reason 7 is in the “middle” of the scale is because the natural dissociation of water sits at equilibrium at 10^-7 M at 298K, IIRC. So perturbations naturally just displace that specific equilibrium, so it absolutely is normative to water.
CookieOfFortune@lemmy.world 4 weeks ago
WalrusDragonOnABike@reddthat.com 4 weeks ago
The exact value varies with temperature, so it’s a “good enough for the typical variations in temperature experienced by most aqueous solutions” estimate.
NielsBohron@lemmy.world 4 weeks ago
Interestingly enough, in other solvents a neutral pH is going to be a different value. IIRC, ammonia has an autoionization constant of 10^-30, so a neutral pH would be 15