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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pH indicator that will fluoresce under UV light
I'm interested in a pH indicator that will strongly fluoresce under a typical black light that anyone could buy. I want to use an acid base reaction to get an idea of how fast two liquids mix in a ...
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24 views
Change in pH when changing the sequence of acidic solution
I have 4 acidic solutions: Barium nitrate, aluminium nitrate monohydrate, cobalt nitrate hexahydrate, and hexachloroplatinic acid. Everything is dissolved in water.
I mixed them in order to create a ...
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Why is HI more acidic than HF? [duplicate]
The more will be the polarity, the more will be the solubility, and the more will be the acidity too between HF and HI. Can anyone please tell me which is more acidic between HF and HI?
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Titration and Neutralization percentages [closed]
When one adds a 0.10 M NaOH solution to a weak acid solution, a portion of the weak acid solution is neutralized. If 20.8 mL of a 0.10 M solution of NaOH is needed to completely (100%) neutralize 10 ...
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Determine the pH and pOH of pure water at 50 °C [closed]
Determine the pH and pOH of pure water at 50 °C.
I’m not sure what formulas to use on this problem.
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2answers
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Is it correct to say that active carbon is an enhancer of either acid or base?
As a non chemist I tried to read to understand if active carbon acts in solutions as an acid or a base but I understood that it can act as both, depends on the material which used to make the solution....
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Is there a difference between hand soap and body soap with killing viruses? [closed]
With the Coronavirus in full swing around the globe, I wanted an answer to this, particularly since my dad has just been diagnosed with Leukaemia.
We can't find hand wash anywhere but instead I just ...
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2answers
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Creating a buffer with with a target pH and given weak base?
I need to create a $100\textrm{mL}$ buffer of $\textrm{pH = 9.20}$ with ammonia and ammonium chloride such that $\textrm{pH = }9.20\pm0.50$ with $20\textrm{mL}$ of $0.2\textrm{M } \ce{NaOH}/\ce{HCl}$. ...
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Why do amino acids exist as zwitter ions in the solid state? [closed]
I was going through the ionization of amino acids and came across the concept of zwitterions. I assume that zwitterion existence in the aqueous state is pH driven. Pka of cooh in amino acids is ~2 and ...
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1answer
68 views
What does it mean to accept or donate a proton? [closed]
I've been trying to find out the answer to this question but can't seem to find it anywhere. I would like a very simple explanation.
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30 views
Hydrochloric acid substitute in an Iron-gall ink solution
Recently I started experimenting with making my own ink to be used in fountain pens.
I was wondering if hydrochloric acid in an iron-gall ink is used to prevent sediment ONLY by lowering the pH of ...
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1answer
39 views
The rate of change in pH v.s Temperature
I have somewhat established that there is a linear relationship between change in pH of carbonic fizzy drinks over time. I also realise that the pH increases linearly faster for the same carbonated ...
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1answer
35 views
Why is the pH of rainfall much lower than pure water? [duplicate]
Like it says on the tin. Several sites say that the pH of rainfall is somewhere between 5 and 5.5, and a few seem to suggest that it averages around 5.7. But why is the pH of rain much lower than that ...
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2answers
139 views
What is the difference between Half Equivalence point and Equivalence point?
OKay I learned in class that equivalence point is the time of neutralization, where the # of moles of acids and base present is in equivalence/same amount.
Now I was also told that Half equivalence ...
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2answers
412 views
How does pH of soda drink vary with time
Basically I have done an experiment where I measure the pH of my soda drink at a specific temperature over $\pu{45 min}$. At every temperature, the $\mathrm{pH}$ of my soda drink increases, but much ...
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26 views
How do you find the ph of lime juice through titration?
I am doing an experiment on the effect of time on the pH of Lime juice.
I was wondering how you would calculate the pH through titrations using 1 Molar NaOH. I have been racking my brain on this for a ...
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1answer
44 views
Why does the concentration of the acid equals that of the base at the mid-point of titration? [closed]
Consider this graph of the titration of a weak acid and a strong base:
The buffering region is strongest at the midpoint of titration because there is equal concentrations of acetic acid and its ...
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2answers
89 views
Why is H⁺ ion considered the source of acidity, and OH⁻ considered the source of basicity? [closed]
As the title implies, what caused the association between $\ce{H+}$ and acidity, and between $\ce{OH-}$ and basicity?
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How will the dielectric constant of water change when ethyl acetate is added?
How will the dielectric constant of water change when ethyl acetate is added?
The $\mathrm{p}K_a$ value of weak acids in aprotic solvents will be lower than in protic solvents because the dielectric ...
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1answer
63 views
Accurate method to calculate the pH of a salt from a weak acid and weak base
Can someone help me with this?
The problem is as follows:
Find the $\mathrm{pH}$ of $\pu{1M}$ solution of $\ce{NH4CN}$. Their respective
hydrolysis constants are:
$K_h = 5.6\times 10^{-10}$
...
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0answers
18 views
How to find the molar concentration of two compounds mixed together in a buffer solution having the Kb and its Ph [duplicate]
Calculate how many milliliters of a $\pu{8.00 \times 10^{−1} M}$ solution of $\ce{NH3}$ and how many milliliters of a $\pu{7.80 \times 10^{−1} M}$ solution of $\ce{NH4Cl}$ are needed to get to a liter ...
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38 views
pH responsive polymer which is immiscible in water?
Can anyone suggest a pH-responsive polymer, which is immiscible in water (polar solvent) but miscible in oil (e.g vegetable oil)?
I want to study the change in the density of such polymers when they ...
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1answer
23 views
How does increasing the Hydrogen Concentration of CuSO4 (electrolyte) affect electroplating of copper
I'm trying to find an answer as to how lowering the pH of the CuSO4 solution during electroplating of copper affects the amount of copper deposited onto the cathode.
My very basic understanding is ...
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1answer
51 views
Finding Ka of a monoprotic weak acid from pH and concentration of added sodium salt
A solution of $\pu{0.36 M}$ of the sodium salt of a generic monoprotic weak acid $\ce{HA}$ has a $\mathrm{pH}$ value of $8.782.$ $K_\mathrm{a} = ?$
Why doesn't the following formula work in this ...
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1answer
51 views
Can ascorbic acid be neutralized and keep it's elastic properties in dough?
Ascorbic acid (C6H8O6) is commonly used in dough to give it strength and elasticity. However, I need this dough to be alkaline, or at the very least neutral. I've used sodium carbonate (Na2CO3) before ...
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2answers
62 views
pH of amphoteric species
For a solution of $\ce{HA-}$, I have seen the following approximations for the $\mathrm{pH}:$
$$\mathrm{pH} = \frac{1}{2}(\mathrm{p}K_\mathrm{a1} + \mathrm{p}K_\mathrm{a2})\tag{1}$$
$$\mathrm{pH} = \...
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3answers
89 views
Tap water pH adjustment using citric acid
I've lowered tap water pH from 7 to 6 using citric acid. After couple of hours pH raised again to 7.
What is the reason for this raise? Citric acid overcomes waters buffering feature then raise the $...
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3answers
98 views
How to simplify these system of equilibrium equations
What is the pH when $0.025$ mol $\ce{NiCl2}$ is added to $\pu{1.00 L}$ of a $\pu{0.100 M}$ solution of $\ce{HCN}$, if the formation constant for $\ce{Ni(CN)4^2-}$ is $K_f=\pu{1.0e22}$, and the $K_a$ ...
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2answers
94 views
Acidic nature of boric acid when its concentration high
Following statement was given for boric acid $(\ce{H3BO3}):$
At low concentrations $(\leq\pu{0.02 M})$ essentially $\ce{B(OH)3}$ and $\ce{B(OH)4-}$ are present, but at higher concentration the ...
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0answers
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Acidity comparison on R-PO3H2
Question
Compare the acidity $(K_\mathrm{a1})$ of the following three acids:
$\ce{H3PO4},$ $\ce{Ph-PO(OH)2}$ and $\ce{H3C-PO(OH)2}.$
Thoughts
These three acids are of type $\ce{R-PO3H2},$ where ...
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2answers
169 views
Use of Concentration for pH
When we find the pH of a solution, do we use normality or molarity? My teacher said that if the compound is present by itself, we can use normality but in all other cases we should use molarity. Can ...
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3answers
144 views
Fitting multiple pKa's
I have three histidine residues that are next to each other in a protein. When I compute the fraction of unprotonated states for each individual histidine as a function of $\mathrm{pH}$ my titration ...
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2answers
161 views
Calculating pH of rain water
The concentration of $\ce{SO2}$ in the atmosphere over a city on a certain day is $\pu{10 ppm}$. Given that solubility of $\ce{SO2}$ in water is $\pu{1.3653 mol L-1}$ and $\mathrm{p}K_\mathrm{a}$ of $\...
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1answer
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Is there a relationship between acidity of the water solution and oxidation/reduction reactions?
What I want to know is if there is a relationship between the acidity of the water solution and redox reactions and if there is a relationship what favors the oxidation and what favors the reduction? ...
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Is contribution to pH by an acid or base always greater than salt hydrolysis?
I was solving a titration question and the reaction I came to was this:
$$
\begin{array}{lcccc}
\ce{&BOH(aq) &+ &HCl(aq) -> &BC(aq) &+ &H2O(l) }\\
\text{Initial} & x &...
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How to clean pocket pH meter before storage?
Hello.
I read about different methods how to clean this specific(attached photo)pocket pH meter before storage and i can't figure out what is the right way.
One method says to stir the pH meter(...
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2answers
51 views
Can I make a buffer with a weak acid without adding it's conjugated base, when the desired pH of the solution is exactly the pKa of the weak acid?
An acid will be 50% dissociated when the solution it's in have a pH equal to the acid pKa ('afirmation 1', for later reference).
We also know that a good buffer solution have equal concentrations of ...
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1answer
91 views
pKa of phenols using UV-Vis spectroscopy
I have done an experiment where I dissolved four different substituted phenols in acidic, basic, and buffer solutions, and recorded the UV-Vis spectra for each. I'm supposed to pick a wavelength where ...
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0answers
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What is the pH and pKa relationship of LaCl3 in water and its precipitant La(OH)3?
In light of this question and its answers, I hope to get some insights into the $\mathrm{pH}$ of $\ce{LaCl3}$ in water and its $\mathrm{pH}$ relationship to $\ce{La(OH)3}$ precipitant's $\mathrm{p}K_\...
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1answer
80 views
How to calculate the number of protons in a sphere given the volume and the pH?
The spherical radius of a nano-droplet of a solution ($\mathrm{pH}$ of which is $6$) is given as $\pu{20nm}$.
I can find the molar concentration of $\ce{H+}$ and subsequently the number of $\ce{H+}$ ...
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0answers
53 views
Hydronium ion concentration to compare pH values
I'm having a bit of trouble with this question:
Which has a higher $\mathrm{pH}$ value, $\pu{0.001 M}$ $\ce{HCl}$ or $\pu{0.1 M}$ $\ce{CH3COOH}$ $(K_\mathrm{a} = \pu{1.8E-5})?$
I have calculated ...
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How to calculate Revelle factor using only pH, DIC and TAlk for seawater?
I have the temperature, salinity, $\mathrm{pH},$ dissolved inorganic carbon (DIC) and total alkalinity (TAlk) values for an estuarine water sample. I want to calculate the Revelle factor.
The Revelle ...
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0answers
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Calculating pH of a saturated weak acid/base solution [closed]
How can you calculate the $\mathrm{pH}$ if you know for example the $\mathrm{p}K_\mathrm{a}$ or $\mathrm{p}K_\mathrm{b}$ value of a weak acid/base and how much acid/base can dilute in water. Let's ...
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1answer
297 views
Is black tea a pH indicator?
Today, I made a cup of lemon tea in a different way than usual. Instead of pouring hot water in to a mug containing lemon juice and black tea (my normal routine), I let the tea steep for a little ...
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2answers
70 views
Finding pH of acid in water [closed]
How would you find the pH of an acid dissolved in water? Would you need to take the fact that the pH of water is already 7 into account and go on from there?
Say, for example, that you add 0.0500 mL ...
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1answer
90 views
Why CO2 is not reducing the pH of NaOH as the way it is expected
I am using $\ce{CO2}$ for the reduction of pH of $\ce{NaOH}$ solution ($\pu{2.5g}\; \ce{NaOH} + \pu{250ml}\; \ce{H2O}$, with $\mathrm{pH}\; 13+$).
I am introducing $\ce{CO2}$ with different dosages ($\...
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1answer
213 views
Preparation of acetate buffer from sodium acetate and hydrochloric acid
A $\pu{1.0 L}$ buffer solution of $\mathrm{pH}~4.43$ is made up of $\pu{0.30 M}$ sodium ethanoate and $\pu{0.20 M}$ $\ce{HCl}$ solutions. Calculate the volume of sodium ethanoate and $\pu{0.20 M}$ $\...
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Is pH in a charged hydrogel and its supernatant solution constant?
Let us assume we deal with ideal systems without interactions.
The gel phase and the supernatant solution phase are in thermodynamic equilibrium. The supernatant solution shall consist of different ...
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143 views
Can a universal indicator turn colorless?
I learned that litmus paper could be bleached by chlorine to turn colorless. I’m wondering if any chemical substances can react with all the components of a universal indicator such that it turns ...
2
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1answer
178 views
Ratio of uncharged to charged side chains [closed]
The $\mathrm{p}K_\mathrm{a}$ of the side chain imidazole group of histidine is $6.0.$ What is the ratio of uncharged to charged side chains at $\mathrm{pH}~7?$
Here's my attempt to the solution:
$$7 ...
