Questions tagged [ph]
pH (or the potential of hydrogen) is a scale used to measure how acidic or basic an aqueous solution is.
632
questions
-2
votes
0answers
23 views
How do you calculate pH, with different types of acids in solution? [closed]
New question
41.0 mL of 0.0150 M hydrochloric acid, 130 mL of 0.0650 M hydroiodic acid and 55 mL of 0.00680 M sulfuric acid are pipetted into a 250 mL volumetric flask, which is then filled up to the ...
-2
votes
0answers
16 views
In the picture below, which one is acidic, alkalalinse and neutral [closed]
Which form do you think is present at acidic pH, which one in neutral solutions, and which one in alkaline solutions? Briefly justify your answers, based on the availability of protons at different pH ...
-2
votes
0answers
20 views
How to calculate pH of final solution using volume and pH of initial solutions? [closed]
When two solutions of equal volume with pH 2 and 8 are mixed, what happens to resulting pH ? How to calculate the final pH?
I am being too specific this time.
1
vote
0answers
44 views
Calculating ionic strength and pH of a buffer solution [closed]
Im trying to calculate ion strength and pH of solution.
Components of the solution:
47 ul of 1000 pmol DNA in Elution Buffer (10 mM Tris-HCl pH 8.5) was bound to 3 ul of 10 µM YoYo1 (flourescent dye) ...
-1
votes
1answer
34 views
How can I prepare two phosphate buffer of different concentrations but give same pH? [closed]
How is it that buffers of different compositions can have the same pH? For example, it is possible to prepare 0.01 M phosphate buffer of pH 7.0 and 0.1 M phosphate buffer of pH 7.0? How?
I used ...
1
vote
1answer
42 views
Why can Neutral Red (indicator) not test values below its pKa?
It is the only indicator I have found that does not test below its pka, and can't think of any reason for this.
Neutral Red has a pKa value of 6.8.
(
Reference 1,
Reference 2
),
but looking at its pH ...
1
vote
1answer
45 views
How a titration curve is affected when a poorly soluble salt is formed?
Suppose that I have $\pu{100 mL}$ solution of strong acid, $\ce{HA}$, at $\pu{0.10 mol L^{-1}}$.
This solution is titrated with a strong base solution, $\ce{BOH}$, at $\pu{0.10 mol L^{-1}}$.
Suppose ...
2
votes
0answers
19 views
How to control pH in a fermenter based on the acid produced by mircoorganism
I have got a bioreactor with an aqueous medium which produces biomass (yeast; S.cerevisiae) after inoculation.
I am observing and collecting data over the whole process via probes/etc. on different ...
-2
votes
2answers
59 views
Finding the pH of the solution
In this video, at 3:30 min professor solves two equations
$$\ce{H2O —> H+ + OH-}$$
and
$$ \ce{HCl —> H+ + Cl-}$$
and deduces $[\ce{H+}] = [\ce{Cl-}] +[\ce{OH-}]$. How come this happen from ...
0
votes
0answers
19 views
pKa values for amino acid
To calculate the pI value, we take the average of the pKa values from the 2 groups that result in a net charge of 0.
For that to happen, the pKa values should be at the midpoint of titration where ...
-1
votes
1answer
38 views
How to predict whether a salt will act as an acid or as a base in aqueous medium? [closed]
How to would we know if a salt such as $\ce{CO_2}$ reacts acidic or basic in water.
The explanation I see everywhere is that you have to see the acid and base that makes up the salt, in the case of $\...
1
vote
1answer
26 views
The time-dependent pH value in a fermentation
I want to know if someone has supporting tips or solutions to my problem:
In biotechnology, fermentations are used to grow microorganisms. These need a specific media/broth in which temperature, pH, ...
-3
votes
1answer
54 views
How does sodium carbonate reduce pH?
Sodium carbonate is used in pools to raise pH. From my understanding, it would dissociate in water like so:
$$\ce{Na2CO3 <=> 2 Na+ + CO3^2-}$$
To raise pH, doesn't it have to absorb hydrogen ...
3
votes
0answers
31 views
Effects of gamma irradiation on pH buffer
Does anybody know if it is possible to gamma-irradiate a bottle of pH buffer to sterilise it? Are there any known effects (short-term or long-term) of the irradition process on the pH qualities of the ...
0
votes
0answers
45 views
What is the pH of a solution of iron acetate?
What is the pH of a $\ce{0.1 M}$ solution of $\ce{Fe(CH_3COO)_3}$? I'm not sure how to do this, as it would involve complicated mass balance equations, but I think I can apply the approximation $\ce{...
1
vote
1answer
42 views
Acid solution — lower pH when diluted
Today I came across a "thought experiment" regarding $\mathrm{pH}$ of a diluted acid solution. This idea looks somewhat logical but obviously contradicts the reality. Can you show me where is the ...
0
votes
3answers
65 views
Doubt on process to calculate pKa [closed]
I have to solve an exercise that I've been trying for a long time without success.
Information that I have:
pH @ certain temperature of an aqueous dissolution of an acid
molar concentration ...
1
vote
1answer
64 views
Titration of barium(II) hydroxide by hydrochloric acid
$\pu{25 ml}$ of $\pu{0.024 M}$ $\ce{HCl}$ is titrated into a volumetric flask which initially contains $\pu{45 ml}$ of $\pu{0.034 M}$ $\ce{Ba(OH)2}$. Calculate the $\mathrm{pH}$.
This is how I ...
1
vote
2answers
48 views
Calculating amount of base needed to achieve a specific pH in a mixed ethanol-water solvent
I'm looking for some way to calculate how much base I will need to add to an unbuffered solvent consisting of a mixture of ethanol and water in order to basify it to a specific reading (10) on an a pH ...
1
vote
0answers
18 views
Why might litmus paper and universal indicator give conflicting pH readings in an acid-carbonate reaction?
The resulting neutralised (which wasn't actually neutralised due to not realising CaCO3's insolubility) solution between Hydrochloric Acid and Calcium Carbonate, as per balanced equation
CaCO₃ + 2HCl ...
-3
votes
1answer
30 views
Acid/Base Indicator [closed]
I'm not sure how the concept and math work on this problem. Can someone show me how you can get the answer, both conceptually and using math?
-2
votes
1answer
26 views
Calculating the pH of Strong Acid Solutions [closed]
Calculate the $\mathrm{pH}$ of a $\pu{1.5e–11 M}$ solution of $\ce{HCl}.$ How is the $\mathrm{pH}~7?$
2
votes
1answer
74 views
Why does pH of a buffer solution change according to Henderson–Hasselbalch equation? [closed]
If I add a little amount of acid or base to a buffer solution, the pH of the buffer won't change. That's what the diagramatic mechanism tells us.
But according to Henderson–Hasselbalch equation, the $...
0
votes
0answers
21 views
What is the cause for the difference in pH between NaCl and Ringer Lactate
Reading this article, I came across a passage which got me to think of this question:
"Normal saline contains approximately $\pu{154mM}$ of each $\ce{Na+}$ and $\ce{Cl-}$ with average pH of 5.0 and ...
1
vote
0answers
28 views
Acid and base separation on an anion exchange column [closed]
I'm new with this concept and so I would need some advice.
I want to separate an acid and a base in a water solution. The acid has $\mathrm{p}K_\mathrm{a}(\ce{HA}) = 5$ and the corresponding acid of ...
0
votes
0answers
55 views
Calculate the pH
Calculate the pH of a dissolution of 100 ml of 0.1 M solution of ammonium chloride in the style of 100 ml of 0.1 M hydrochloric acid solution
$\ce{NH4Cl -> NH4+ + Cl-}$
$\ce{HCl -> H+ + Cl-}$
...
2
votes
0answers
51 views
How does a pH glass electrode work?
Every source I read mentions the potential difference building up at the glass membrane (according to the Nernst equation). But how is this difference actually measured? Sticking an electrode into a ...
1
vote
1answer
108 views
Calculating pH when weak base is added to an strong acid
$\ce{NH3}$ solution of $\pu{0.1 mol dm-3}$ is being added to a $\pu{25.0 cm3}$ of $\pu{0.1 mol dm-3}$ $\ce{HCl}$ solution. Calculate the pH of the solution when volume of added $\ce{NH3}$ solution is $...
2
votes
1answer
58 views
Can I use litmus paper to test unknown liquid that contains a concentrated strong acid?
Can I use litmus paper to test unknown liquid that contains a concentrated strong acid (example $\ce{H2SO4}$)? Can concentrated strong acid destroy litmus paper?
1
vote
1answer
44 views
Will strong concentrated acid destroy litmus paper and pH paper if they are dipped in acid?
I am curious to know what will happen if I have litmus paper and pH paper, and I dip them into strong concentrated acid like conc. $\ce{H2SO4}$ to test its acidity or basicity. Will acid destroy ...
2
votes
1answer
53 views
Confusion regarding calculating the pH of a salt of weak acid and weak base
I need to calculate the $\mathrm{pH}$ of a salt of weak acid and weak base in an aqueous solution.
Method I used for calculation
For a salt of weak acid and weak base (assuming complete dissociation ...
1
vote
0answers
54 views
Can Acids have pH of more than 7? [duplicate]
Consider a solution of $\text{HCl}$ with a concentration of $10^{-10}$ $\text{M}$. Now, if I find it's pH:
$$\text{pH} = -\log([\text{H}^+])$$
$$\text{pH} = -\log(10^{-10}) = 10$$
At room temperature, ...
1
vote
0answers
27 views
Measuring pH in ferric oxalate solutions
I have a problem with measuring $\mathrm{pH}$ in ferric oxalate solutions ($\sim 5~\text{to}~\pu{10 g L-1}$ $\ce{Fe},$ $\pu{0.8 M}$ oxalic acid, $\pu{25 °C}$). While I am sure about the $\mathrm{pH}$-...
0
votes
0answers
47 views
Calculation of resultant pH
A solution with $\mathrm{pH}=4$ is mixed with a solution with $\mathrm{pH}=10$ in equal volumes. Calculate resultant $\mathrm{pH}$.
Please note both solution consists of strong acids and/or bases i....
1
vote
1answer
51 views
Calculate the pH of buffer solution
PROBLEM: A solution was prepared by mixing $\pu{25.00 mL}$ of $\ce{NaOH}$ $\pu{(c = 1mol/L)}$ and $\pu{10.00 mL}$ of acetic acid $\pu{(c = 2.5 mol/L)}$ in water to give $\pu{250 mL}$ of solution.
...
1
vote
1answer
55 views
Why is the pH level of carbonation loss decreasing then increases afterwards?
We have done an experiment of the titration of unsealed sprite soda to find the amount of carbonic acid being loss on various duration (0 to 1 hour), due to decrease pressure.
The calculation was to ...
1
vote
0answers
28 views
Do TDS meters measure HCO₃⁻/CO₃²⁻?
I am trying to add $\pu{2 g}$ of $\ce{KHCO3}$ to $\pu{20 L}$ of RO water $(\mathrm{pH} = 5.2)$ which theoretically it will add
$$
\begin{array}{lr}
\hline
\ce{K+} &\pu{10.32 ppm} \\
\ce{HCO3-} &...
1
vote
0answers
43 views
Is it possible to raise pH in RO water without Na, Mg, K, Ca, S addition?
Maybe the question in the title is simple (=stupid) and the answer is 'simple No' but I have the urge to ask.
Some background, I have an aquarium which I use RO water and I use some portions of $\ce{...
-3
votes
2answers
104 views
pH of strong acid weak acid mixture [closed]
Question: $\ce{H2S}$ ($\pu{0.1M}$; $K_\mathrm{a} = 1.2×10^{-20} $) and $\ce{HCl}$ ($\pu{0.3M}$) with same volume are mixed together. What is the resultant $\mathrm{pH}$?
My approach:
Let the volume ...
2
votes
1answer
42 views
Calculating molecular weight of an acid based on given values of mass, volume, pH and pKa
This is what I thought was an easy problem but according to a given answer I am doing it wrong:
$\pu{11 mg}$ of a monoprotic acid was dissolved in $\pu{0.5 l}$ of water. The resulting $\mathrm{pH}$ ...
1
vote
1answer
124 views
Why do weak acids like ethanol not act as a strong base in water?
In water, ethanol has a $\mathrm{p}K_\mathrm{a} = 15.9$ which means that its $\mathrm{p}K_\mathrm{b}$ is $-1.9$. Which implies that all weak acids in water are in fact strong bases. But this is not ...
1
vote
1answer
73 views
Calculating the ph of an unknown solution by measuring the precipitate [closed]
You have an unknown metal hydroxide, but no meters or indicators. You have lead (II) nitrate, which is soluble in it, and lead (II) hydroxide that is insoluble in it. You take one liter of the unknown ...
0
votes
0answers
48 views
Calculating pH of solution
What is the $\mathrm{pH}$ when you dissolve equal amounts of $\ce{NaHCO3}$ and $\ce{Na2CO3}$ in water?
When both of the compounds are dissolved, we will have equal amounts of $\ce{HCO3-}$ and $\ce{...
1
vote
1answer
39 views
Calculating pH of weak base and strong acid: Why is K(a) not required?
Question: 35mL of 1.5M $\ce{HCN}$, a weak acid(K(a)= $6.2*10^{-10}$) is mixed with 25mL of 2.5M $\ce{KOH}$. Calculate the pH of final solution.
The solution given in my textbook is as follows:-
$\ce{...
1
vote
1answer
34 views
Could this solution be resolved by titration?
I have a mixture of $\ce{NH_4NO_3}$ and $\ce{NH_3}$ at $\ce{pH}$ of about 13.
It is possible to determine the concentration of both on them by acid-base titration?
I was told it's possible, and that ...
1
vote
1answer
31 views
When there is an increase in temperature, how is the pH of the ocean affected? (Question is related to ocean acidification)
This is my current understanding:
Ocean acidification is the result of atmospheric $\ce{CO2}$ dissolving in the ocean's water. When this occurs the $\mathrm{pH}$ of the ocean decreases (from the ...
0
votes
1answer
40 views
pKa value of an indicator
Can we deduce the actual value of $\mathrm{p}K_\mathrm{a}$ of an indicator if the $\mathrm{pH}$ range has been given?
I know that $\mathrm{pH}$ range is physically the range of values over which an ...
1
vote
2answers
57 views
Citric acid and ammonium nitrate
Soil based question. I have soil with to much Ammonium Nitrate in it. I am wondering if I use citric acid and water mixed will that flush out the extra Ammonium Nitrate that has built up in the soil.
...
2
votes
2answers
75 views
Can I use the Henderson–Hasselbalch for calculating the pH of non-buffer systems?
Can I use the Henderson–Hasselbalch equation on reactions that are not buffers? When I read up on the derivation of the equation, I noticed that there is absolutely no assumption on the relative ...
1
vote
0answers
25 views
Impact of pH? Change in Binding Affinity of protein-ligand complex based on pH and Kd?
When the $\mathrm{pH}$ was $5.0$, the temperature was $\pu{25 °C}$,the $K_\mathrm{D}$ was $\pu{5 μM}$, and [L] was equal to $K_D$, the protein(s) were half bound.
Question considers half bound ...
