# Tag Info

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"Hydronium" content can be easily determined by simple acid base titration. Keep in mind that there is nothing fundamental about pH. It is just a convenient scale for expressing hydrogen ion concentration. For example, a kilogram is a recent invention for expressing mass measurement, it does not mean that ancient people did not weigh anything ...

3

You did not mention what kind of waste water are you talking about. Is it from a textile industry, paper mill, leather factory? Waste water is not a "compound", it can be any junk and its pH can vary over several orders of magnitude! As I have stated before, there is nothing fundamental about pH. It is a scale of convenience. It can be negative and ...

2

Maybe a numerical example will help you. Let's start from pure water, with the following concentrations :$\ce{[H+] = [OH-] = 10^{-7} M}$. Now we will suppose you add $\ce{10^{-7}} mol$ $\ce{HCl}$ in one liter of this water. Suddenly, the concentration of $\ce{H+}$ should double. This is not possible in the long run. A part $a$ of these supplementary $\ce{H+}$...

2

I like what Maurice said "When nobody understands a scientific phenomena, we give it a name. Here the name is overpotential. Here the hydrogen is said to have a big "over potential" on mercury cathode. That is a bright and remarkable way to hide our ignorance." This is little on the extreme side but people have spent their life on ...

1

This question and the one referenced by Mithoron address NH$_4$HF$_2$ as an entity in itself which must be examined as a whole. It is easier conceptually to rewrite the formula for the compound as NH$_4$F.HF. Consider adding NH$_4$F to water: you get a pH near 7. In a separate container, add HF to water (~0.1 M); you get a pH ~1 https://ehs.princeton.edu/...

1

Aluminum pieces are always covered by a thin, waterproof and nearly monomolecular layer of alumina, or aluminum oxide $\ce{Al2O3}$. This layer prevents the aluminum metal to get in touch with water. Because, pure and non-protected aluminum would immediately react with water according to : $$\ce{2 Al + 6H2O -> Al(OH)3 (s) + 3 H2 (g)}$$ This reaction ...

1

The general approach to solve acido-basic equilibrium problems is: respecting charge balance and charge conservation respecting mass conservation respecting dissociation equilibrium constants for acids, bases and water itself. Generally, it leads to a set of nonlinear equations for a set of independent variables. The application of a substitution method ...

1

Solutions of aluminum sulfate are highly acidic. The Merck Index states that at a concentration $0.2 M$, the pH is $3.0$.

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