Because those can leak and cause cancer
Being given the hydronium (or simply the hydrogen) ion concentration (molarity), one of the easiest properties of the solution to determine is its pH. The pH of a solution indicates the acidity (or basicity) of a given solution. The typical pH range of solutions is from 1 to 14, with 7 being neutral, 1 to 6 being acidic, and 8 to 14 being basic.
To determine the pH of a solution, the negative log (-log) of the hydronium/hydrogen ion concentration (molarity) of the solution is calculated. Thus (assuming that the given hydrogen ion concentration is in molarity (mol/L)),
pH = -log(

) or -log(

pH = -log (<span>7.94 × 10−6 mol/L)
pH = 5.13Because the pH is less than 7 (within the range 1 to 6),
then the black coffee solution is acidic. </span>
Suppose protons were emitted rather than electrons then it affects the experiment as the mean velocity of proton will be less then mean velocity electron .
The mass of proton is greater than the mass of electrons but charge of electron is equal to the charge of proton . So , due to difference in the mass of electron and proton there will be some effects. We can conserve the electric energy which is equal to the qe .
The kinetic energy = 1/2
Now changing the electric potential energy into kinetic energy
v = √2qe/m
The mean velocity of proton will be less then mean velocity electron .
To learn more about proton
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