Stands for Potential of Hydrogen and is a measure of how acidic or basic an aqueous solution is.

learn more… | top users | synonyms

0
votes
0answers
14 views

The potential range of the cyclic voltammetry of CoCat in KPi made of D2O

I have a phosphate buffer adjusted to pH 7, and another phosphate buffer made of deuterium oxide (D2O) adjusted to pH 6.6 (pD 7). I want to conduct cyclic voltammetry of cobalt oxide catalyst in these ...
3
votes
1answer
58 views

How to calculate pH of a solution when H3PO4,NaH2PO4,Na2HPO4 and Na3PO4 are mixed together in certain amounts to form a solution?

How to calculate pH of a solution when $\ce {H3PO4}$ ,$\ce {NaH2PO4}$,$\ce{Na2HPO4}$ and $\ce {Na_3PO_4}$ are mixed together in certain amounts to form a solution? I know how to calculate pH when ...
0
votes
0answers
27 views

What is the PKa of hexafluorosilicic acid?

I've tried Googling this for about an hour and couldn't find the information on any Chemistry resource sites. Given the formula F6H2Si, is it possible to calculate the PKa, or can this only be worked ...
0
votes
1answer
41 views

What actually happens when citric acid is added to a highly alkaline soap solution?

A few days ago I made an experiment. I diluted a few small chunks of bar soap with 20 ml of water. I then measured the ph of the solution which was around 10. I then added a tiny amount of citric ...
0
votes
1answer
39 views

Calculation of Ka and pH

$$\ce{H3PO4 <=> H+ + H2PO4-}$$ $$K_{\mathrm a1} = 7.4\times10^{-3}$$ $$\ce{H2PO4- <=> H+ + HPO4^2-}$$ $$K_{\mathrm a2} = 6.2\times10^{-5}$$ $$\ce{HPO4^2- <=> H^+ + ...
3
votes
2answers
39 views

How to determine pH of food in order to avoid unsuitable storage containers

In an acidic (lemon-containing) sauce I had placed a metallic spoon. A few days later it had a metallic taste. Stainless steal might be a significant source of nickel, chromium and iron [1]. Also, ...
4
votes
1answer
65 views

Is there any reason to fear personal exposure to rain with a pH of 3.1?

Where I live now there can be significantly acidic rain. The government posts measurements for many cities and there can be stretches for days or longer with reported pH of 3.2 or 3.1. I even saw 2.9 ...
3
votes
1answer
34 views

Dissolving Tylenol Science Experiment - why is it fastest in distilled water?

My son has a science experiment for class to dissolve Tylenol (325mg acetaminophen) in 3 different solutions (125 mL volume each): Distilled water Vinegar (1 part white vinegar to 4 parts water) ...
0
votes
0answers
11 views

Determining the min/max change a fluid can exert over a different fluid's pH

...assuming you know the pH of both fluids, but not the chemical structure. Suppose we mix: 50ml of mystery fluid A @ 7.4 50ml of mystery fluid @ 6.4 Is there a shortcut to determine what the ...
-3
votes
1answer
52 views

Is NaH2PO4 and Na2HPO4 buffer a neutral buffer? [closed]

My teacher mentioned in class that a mixture of two salts derived from polybasic acid functions as a buffer solution. But is it a neutral buffer or acidic buffer?
1
vote
1answer
48 views

Which pH approximation to choose when?

When I learned about pH approximations in school, I was told that each approximation fits to a certain acidity strength/pKa range. Those ranges are grouped in common categories (pKa borders are only ...
4
votes
2answers
215 views

pH of a buffer made with H3BO3 and KH2BO3

The Problem Calculate the pH of a buffer that is 0.200M $\ce{H3BO3}$ and 0.122M $\ce{KH2BO3}$. The $K_a$ for $\ce{H3BO3}$ is $7.3*10^{-10}$ What I Tried For each of these methods, I used 0.200M as ...
-1
votes
1answer
42 views

why the buffer capacity depends on the ratio of salt and acid in acidic buffer?

According to the Henderson–Hasselbatch equation when pH = Pka for any buffer solution then why we say that this is the best buffer?
0
votes
1answer
44 views

Getting the wrong pH value, according to data and online calculator

I'm doing a titration problem with a week acid and strong base, I used experiment data and an online calculator to check my answer, but my pH I calculated is a bit off. Can anyone see where I messed ...
1
vote
1answer
36 views

Glass electrode pH measurement

How is the potential difference between the outer and inner surface of the glass bubble in a glass electrode measured if an Ag/AgCl wire is used as the indicator electrode and Ag/AgCl/KCl is used as ...
7
votes
3answers
200 views

Is LiOH a weaker base than NaOH?

I'm confused about which is the stronger base. Note: I'm not interested in "why," but rather what the "real" pKb values are. $$ \small \begin{array}{lcc} \text{Data for Alkali Metal Hydroxides} \\ ...
1
vote
1answer
26 views

change of pH in urine

I'm looking to lower the pH of a urine solution from 12 to 7. I'm planning to do it in 2 ways. First is to use a strong acid such as HCl. Secondly, using vinegar, a weak acid. However, I am having ...
2
votes
1answer
46 views

Is it possible for a liquid chemical to have a pH value lower than its aqueous solution?

During the QC check of one of the products that we make as a company, the product had a $\mathrm{pH}$ of $10.44$ on one $\mathrm{pH}$ meter and $10.20$ on the other. (The product is a liquid, so it's ...
3
votes
2answers
55 views

How to calculate Ka for hydronium and Kb for hydroxide? [duplicate]

I am wondering how to calculate the $K_a$ for hydronium, $H_3O^+$, and the $K_b$ for hydroxide. Because hydronium undergoes the equilibrium $\ce{H_3O^+(aq) + H_2O (l) <=> H_2O (l) + H_3O^+ ...
1
vote
1answer
56 views

How to get specific concentration of carbonic acid in solution?

I wanted to know if there is a way of getting specific quantities of carbonic acid? Carbonic acid is water + $\ce{CO2}$ but not all the $\ce{CO2}$ dissolves in water. So if I wanted $5\:\mathrm{g}$ of ...
1
vote
1answer
34 views

Why do the first and second ionizations of a diprotic acid produce the same hydronium ion concentrations in solution?

I was going through Oxtoby Chemistry when I got confused by the following passage in the textbook. It said that "two simultaneous equilibria are involved in the ionization of a diprotic acid such as ...
0
votes
0answers
33 views

Why does final pH value of buffer solution after addition of acid not depend on amount added?

I'm brushing up and the example in my book is against my intuition. A buffer solution contains 1.0 mol/L acetic acid and 1.0 mol/L sodium acetate. The solution is at pH = pKa = 4.75. What's the ...
0
votes
0answers
21 views

How to calculate molar concentration of phenol red when mixed with water and a buffer?

The concentration of phenol red is 1E-4 M. The initial volume used was .1 mL and is then mixed with .9 mL of water and 4.0 mL of a .1M borate buffer of pH 9.8. I used a simple M1V1 = M2V2. Where M1 = ...
1
vote
0answers
12 views

pH of a solution 1) disregarding activity and 2) using ionic activity coefficients [closed]

A weak acid with MW= 356 and pKa= 2.76 is dissolved in an isotonic NaCl solution to make a 3% w/v solution. What is the pH of this solution 1) disregarding activity and 2) using activity coefficients ...
2
votes
1answer
46 views

pH Determination

I have a cubic box of length $L=12.42\ \mathrm{\overset{\circ}A}$, containing $60\ \ce{H2O}$ and $1\ \ce{H+}$ ion. What is the $\mathrm{pH}$ of the system? Following the basic definition, ...
0
votes
0answers
27 views

Why does plaster get rusted when exposed to acid solutions?

Why does plaster in the beaker numbered 6, get a brownish color? It is submerged in distilled vinegar with $\mathrm{5\%}$ of acetic acid. Has it oxidized? Has it absorbed the vinegar? what is the ...
1
vote
1answer
31 views

Predicting changes in pH of water when chlorinating using two different methods

Two methods for chlorinating water are using Chlorine gas ($\ce{Cl2}$) or calcium hypochlorite ($\ce{Ca(OCl)2}$). By using chemical equations how can you predict the pH of the water brought about by ...
0
votes
0answers
22 views

Can an acid or base have a pH less than 0 or more than 14? [duplicate]

This question has been asked earlier, but I could not understand it. Please, someone explain it in an easier way.
1
vote
0answers
66 views

Mix 1M Tris/HCl pH 7.5 and 1M Tris/HCl pH 9.5 to get pH 8 [closed]

most of the question is already in the title. I have two pre-made buffer solutions: 1M Tris/HCl with a pH of 7.5, and 1M Tris/HCl with a pH of 9.5. What I need is a 1M Tris/HCl buffer with a pH of 8. ...
3
votes
1answer
64 views

Does a weak buffer solution still maintain a mostly steady pH if the acid or base load it has to buffer is small?

I need to buffer the $\mathrm{pH}$ of a solution to $3.0$ using a citrate buffer. I found a recipe to make a buffer solution that would use $82\%$ of $0.1\,\mathrm M$ citric acid (monohydrate) and ...
1
vote
1answer
94 views

pH 10 to pH9 NaOH dilution

I have a pH 10 NaOH solution. I need to bring down the pH to 9. So I used the $C_1V_1 = C_2V_2$ approach. $C_1 = \mathrm{0.0001~mol/L}$ $V1$ is the necessary amount to produce 10 L of pH9 $C_2 ...
2
votes
1answer
47 views

net charge nucleobases at alkaline conditions

While doing anion exchange chromatography of short oligonucleotide, I have noticed that at $\rm pH=12$, the oligo- retains longer on the column than the same oligo- at $\rm pH=8$. I thought the reason ...
1
vote
0answers
128 views

Find the concentration of the HCl solution when mixed with 1.265g of ACES-K+

$1.265\ \mathrm g$ of N-(2-acetamido)-2-aminoethanesulfonic acid potassium salt (ACES-K+, $M=220.29\ \mathrm{g/mol}$) is dissolved in $88.42\ \mathrm{mL}$ of water. $27.59\ \mathrm{mL}$ of ...
4
votes
0answers
120 views

exchanging H2O in buffer for D2O - pH vs pD?

I have TBS pH 7.4 buffer that I am exchanging all the water out for D2O. How do I find out what the pD is after all the water is gone? I understand that pH meters don't work for deuterium, and it ...
0
votes
0answers
27 views

How to calculate pH of strong base and weak acid flows in a reactor?

I have a bubble column and I would like to calculate the pH that follows, when I have two fluids with different volumetric flow rates coming into the reactor (one is a weak acid an the other is NaOH). ...
1
vote
0answers
8 views

pH, conc vs activity

After studying a somewhat overview of "gamma" activity coefficient (it is not actually in our course but may come in exam as a part of unknown paragraph in ionic equilibrium) I can understand most ...
1
vote
1answer
41 views

Charge of an amino acid sequence

I have the following problem: A polypeptide has the following sequence (amino end on the left) $$\mathbf{lysine - aspartic~acid-histidine-arginine-serine}$$ Using the $pK_a$ information ...
2
votes
1answer
39 views

Why does the acetyl group drop the pH? [closed]

I have a molecule that is 8% of the R groups are replaced with Acetyl groups. When I dissolve it in water it drops the pH. I am trying to understand why.
0
votes
0answers
29 views

pH-dependency of the acidic dissociation of carbonic acid

I know the product of $\ce{CO2 +H2O}$ yields $\ce{H2CO3}$. This is a reversible equation so $\ce{H2CO3}$ goes back to $\ce{H2O + CO2}$. However, my question is: Is there a certain pH which will ...
0
votes
1answer
65 views

Composition and pH of water produced by air conditioners

I would like to know if there are specific studies or research regarding the condensed water that is generated by air conditioners. Many people feel that this water is acid and corrosive but could ...
0
votes
2answers
54 views

Can I use lye as a cooking leavener instead of baking soda?

I asked this question on the cooking site, but got unsatisfactory answers: http://cooking.stackexchange.com/questions/65520/can-i-use-lye-as-a-leavener-instead-of-baking-soda I'm interested to try to ...
0
votes
0answers
72 views

How many grams of MnS will be produced?

1 L of a solution (conc.: $\rm 2\times 10^{-3}~M$ of $\ce{MnCl2}$ buffered with $\rm pH=6$ is saturated with 2.5 L of gaseous $\ce{H2S}$ in standard condition. The final volume is 1 L. How many ...
1
vote
1answer
115 views

Fluctuation in pH reading on pH meter

I was conducting a titration of a saturated $\ce{Ca(OH)_2}$ solution against $\ce{HCl}$ using a pH meter (the kind with a glass electrode). At the beginning of the titration, the pH reading would drop ...
3
votes
2answers
107 views

Understanding how to calculate the pH of a buffer with ice tables

Let's say you are asked to calculate the pH of a solution with: $\mathrm{0.1~M}~\ce{HCl}$ $\mathrm{0.2~M}~\ce{CH3COOH}$. $\mathrm{K_a = 2.10^{-5}}$ This is how I would do it: $$\ce{CH3COOH + ...
0
votes
0answers
55 views

Ph= PKa in a titration of a strong acid with a strong base (or vice versa)

Generaly during the titration of a weak acid/base with a strong base/acid, we can directly read the pKa of the titrand couple which corresponds to the value of half the equivalence volume of the ...
4
votes
1answer
152 views

Why does CO2 lowers the pH of water below 7?

Ok so I understand that having a pH below 7 is considered to be acidic and I also understand that part of the definition of an acid is that it gives off H+ when dissolved in water(even though not all ...
3
votes
1answer
38 views

Mechanism of pseudo buffer pH maintenance

Some solutions, like concentrated HCl, act as buffers even though they lack the buffering component. What is the cause for such a behaviour?
6
votes
1answer
122 views

Is there a relationship between pH indicator colors and the visible light spectrum?

When I examined the colors showed on a pH paper which is red for acids and violet for bases, greenish yellow for neutral and other ranges in between, I noticed that the sequence is exactly same to ...
3
votes
1answer
72 views

Experimental determination of pKa

I have $20~\mathrm{cm^3}$ of a $0.1\ \mathrm{M}$ ethanoic acid solution and have to find out the $\mathrm{p}K_\mathrm{a}$. In experiment this solution had a $\mathrm{pH}$ of $2.91$. Do I use the ...
0
votes
1answer
143 views

Determining the nature of common pH indicators (methyl orange) using Le Chatlier's principle

I got some good information about this topic yesterday, and I understood what I was told, but I have come up with a specific way of phrasing the problem I'm having. It is slightly different than ...