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# Questions tagged [ph]

pH (or the potential of hydrogen) is a scale used to measure how acidic or basic an aqueous solution is.

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### How to calculate the pH of a buffer after HCl was added?

A buffer is made from $50~\mathrm{mL}$ of $1.0~\mathrm{M}$ benzoic acid, $K_a = 6.3\cdot10^{-5}$, and $50~\mathrm{mL}$ of $1.0~\mathrm{M}$ sodium benzoate. a) Calculate the pH of this buffer For this ...
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### Net charge of Peptides at pH1 and pH0

Taking Glycine and aspartic acid. As both the amino acids are fully protonated at pH 0 ad pH 1, how does the peptide bond form? Is it a two step mechanism where the OH from an alpha carboxyl group ...
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### Concentration of hypochlorous acid and hypochlorite

Given a total chlorine concentration and the pH and pKa of $\ce{HOCl}$, how would you find the concentration of $\ce{OCl-}$ and $\ce{HOCl}$ disinfectants? If the given total chlorine concentration is ...
336 views

### Amphoteric amino acid titration

Glycine $(\ce{NH2CH2COOH})$ is an amino acid with two $\mathrm{p}K_a$ values $(\mathrm{p}K_{a,1}=2.0, \ \ce{COOH};\ \mathrm{p}K_{a,2}=10.0, \ \ce{NH2})$. (a) If $0.01~\mathrm{mol}$ of this amino ...
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### pH Changes in primary cells

Primary Cells - pH changes during discharge Alkaline Cell: Manganese Dioxide Zinc Alkaline Cell Anode (-) $\ce {Zn(s) + 2OH^{−}(aq) → ZnO(s) + H2O(l) + 2e^{−}}$ ...
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### What happens when 0.02 mole NaOH is added to a buffer solution?

I am asking this question for my son. (This question is related but we still have our confusions.) We have one liter buffer solution of 4.74 pH which contains 0.1 mole $\ce{CH_3COOH}$ and 0.1 mole ...
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### Using non-food grade NaOH for pH control

I would like to use non-food grade $\ce{NaOH}$ for $\ce{pH}$ water treatment. Any problem with this mixing with water that contains iron? The $\ce{NaOH}$ will be pumped into a well. As a $25\%$ ...
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### Calculating pH of diprotic and amphoteric solutions

I am trying to understand this problem and its corresponding solution (complete solution not shown) First off, from the above one can see that the equilibrium constants when $\ce{H2ASO4-}$ donates ...
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### Given the volumes: determine the pH and the final temperature of a mixture knowing only the initial pH and the temperature of the un-mixed components

I have a pretty basic question but the last time I took Chemistry was in 2007. I am studying the Navy's Nuclear study guide for their interviews and one of the question I am faced with is below. ...
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### Less maintenance-dependent continuous pH testing

I am creating an automated chemical component mixing system (DIY project). One of the features required is continuous monitoring of pH value in my main solution. I do not need it to be very precise, ...
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### What is the pH of 1M Glycerol?

If the pKa of Glycerol is 14.15. How do you calculate the pH for it? I assume that the Henderson-Hasselbalch derivative that works for weak acids and bases is not applicable here.
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### Red Cabbage Indicator colour change with Sodium Metabisulphite

I made some pH indicator by boiling and straining cabbage juice and in an effort to keep it from spoiling for a while without having to store it at fridge temperatures I added some wine making ...
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### Approximate time for pure water pH to equilibrate in open air?

I'm a complete non-chemist, so I don't know how to calculate this, or even what to google for (my searches yielded esoteric research papers). I'm doing some hobby experiments, and I'd like to know ...
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### Calculating approximate pH of polyprotic acids

When I took up ionic equilibria and titrations after a long break, I found it hard to solve the questions regarding pH calculations of polyprotic acds. Consider these two questions as examples:- ...
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### Teeth friendly alcohol drinks

What is the best alcohol for your teeth according to the pH? Is it true that if the acidity of the drink is higher (and ph is lower) than it's worse for your teeth (enamel erosion + bacteria friendly ...
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### What is the pKa of 2-methyl-2,4-pentanediol?

What is the pKa of 2-methyl-2,4-pentanediol? Is there a reference that contains a list of pKa values for various molecules that I can consult or is there a way to determine/estimate the pKa of this ...
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### Why does this shortcut work for calculating pH (proof required)?

My teacher gave me a shortcut regarding calculation of resultant pH if the solutions are mixed and if the difference between the pH of individual solutions is 1. If there are two solutions, the pH is ...
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### What are the properties of various solutions at pH <2 that may cause injuries?

For example, why do some solutions not cause any injuries at pH 2 while HCl does?
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### Isoelectric pH of colloids?

How did we derive the relation between the isoelectric pH and the dissociation constants for the amino and carboxyl groups on zwitterionic amino acids. $$pI=\frac {pK_{a1}+pK_{a2}}{2}$$ where \ce{...
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### Calculating the pH of a solution of Ca(OH)2

A solution prepared by dissolving $2.8 g$ of lime, $\ce{CaO}$ in enough water to make $1.00 l$ of lime water ($\ce{Ca(OH)_{2(aq)}}$). If solubility of $\ce{Ca(OH)2}$ in water is $1.48 g$. The $p\ce H$ ...
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### How to estimate pH?

How you you calculate/estimate the pH of a solution with 3 components all of different pHs? Is there a paper describing this? For example: 0.1M Buffer PCTP at pH 9.5 1.6M Sodium Dihydrogen Phosphate ...
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### Effect of dillution on titration

When we are titrating acid/base using ph meter we add distilled water to immerse the ph electrode. Won't this affect the concentration of the acid/base: I mean isn't this dillution. Won't this ...
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### On the scale of stuff with a pH

I am a confused (and somewhat anal retentive) non-chemist who is trying to understand what pH is. I have come to understand it is a measure of acidity, but I have not yet figured out what that means ...
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### Chemical reasons for choosing Salt Water or Chlorinated pool?

I am currently researching as too which is better for maintaining the chemical balance in a swimming pool. I have obviously tried the standard Google search for ...