# How do acids become alkaline over time? In the experiment a zinc washer was added to hydrochloric acid. The first pH read 0 and at t=14 days, it read 5. Why?

It is not acids that became alkaline; it occurred a reaction between HCl and Zn:$2 H C l + Z n = Z n C {l}_{2} + 2 {H}_{2}$
at the beginning you can see fizz because of Hydrogen that is released in the solution. The reaction stopp itself when the remained amount of HCl is very small (pH =5 means ${H}^{+} = {10}^{- 5} M$)