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

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Sodium fluoride and varying pH - HF risk

I'm looking into conducting an experiment on the adsorption of fluoride (for my International Baccalaureate Extended Essay). As I will be investigating the role of $\mathrm{pH}$ in adsorption ...
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23 views

Neutralization of sodium percarbonate

At the moment, I have been asked to improve the methods given in my experiment to increase the efficiency of the results. One of the steps I am currently looking at is the neutralization of sodium ...
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35 views

How does a lower pH change the alcohol concentration of wine?

I have been told it that when the pH of wine is lowered the alcohol concentration will decrease because of Le Chatelier's Principle. Which states; if a equilibrium is disturbed by changing the ...
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35 views

Determining concentration of salts of polyprotic buffer solution

I'm looking into making a formula for making citric acid buffer solution from citric acid monohydrate ($\ce{C6H8O7.H2O}$) and sodium citrate $\ce{C6H5O7Na3.2H2O}$, with adjustable pH and molarity of ...
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355 views

Can hydrofluoric acid etch glass at a pH of 7.0?

Will it still etch glass when very dilute? Will the reaction still proceed slowly? At what pH will the reaction stop completely? "Although hydrofluoric acid is regarded as a weak acid, it is very ...
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Why does milk clot while making yogurt?

Why does milk clot when it becomes yogurt? Is it only because of the decrease in the $\mathrm{pH}$ of milk? If it does so, what is happening when I increase the $\mathrm{pH}$ level? And by decreasing ...
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95 views

Why isn't CH3OH the most basic if it contains OH?

I was asked to find the most basic solution from the following: $\ce{K2SO4}$ $\ce{CH3OH}$ $\ce{Na2CO3}$ $\ce{(NH4)2CrO4}$ $\ce{BaCl2}$ I know that I have to identify the solution that ...
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Combining acid dissociation constants to determine pH of diprotic acid

If I have a diprotic acid with $K_{\mathrm{a1}}$ and $K_{\mathrm{a2}}$ as the acid dissociation constants, why can't I calculate the final $\mathrm{pH}$ using $K = K_{\mathrm{a1}}\cdot ...
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19 views

Why does the reference electrode in potentiometry have a diaphragm?

I am studying about potentiometry and pH-measurement with a glass electrode. I don't understand why the reference electrode has a diaphragm and is immersed in the measured solution. If I got it right, ...
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What is the pH of ice?

The pH of pure liquid water depends on temperature. It is about pH = 7.0 at room temperature, pH = 6.1 at 100 °C, and pH = 7.5 at 0 °C. What happens to the pH (or to the ion product) of pure water ...
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84 views

Why do acids mix in water faster than bases?

I have $100\ \mathrm{L}$ of water in a tank with an mixer inside and want to know how fast the tank mixes at a given rpm-setting. I am adding $50\ \mathrm{mL}$ of $2\ \mathrm{N}\ \ce{HCl}$ and see ...
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pH of a double buffer

If $1,2,3,4$ moles of $\ce{H3PO4}$,$\ce{NaH2PO4}$,$\ce{Na2HPO4}$ and $\ce{Na3PO4}$ respectively are mixed together to form an aqueous solution of $1$Litre , resulting $\ce{pH}$ is? This question has ...
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22 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 ...
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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 ...
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41 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 ...
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45 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 ...
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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^+ + ...
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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, ...
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69 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 ...
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50 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) ...
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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 ...
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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?
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51 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 ...
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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 ...
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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?
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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 ...
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46 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 ...
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261 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} \\ ...
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32 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 ...
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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 ...
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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^+ ...
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61 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 ...
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38 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 ...
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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 ...
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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 = ...
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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 ...
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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, ...
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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 ...
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32 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 ...
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23 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.
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94 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. ...
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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 ...
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138 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 ...
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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 ...
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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 ...
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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 ...
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28 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). ...
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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 ...
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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 ...
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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.