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 of the Highest Basic Substance [closed]

What is the pH of ortho-diethynylbenzene dianion? If I am correct, it is the most basic substance (superbase)
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Compare the Ka values of the α-H of alkyne and the β-H of alkyl halides

I know that the α-H of alkyne and the β-H of alkyl halides have weak acidic nature, but there is not enough information of their relative strength. Please compare their acidic nature giving suitable ...
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Carbonic acid in pure water

In order to calculate the pH of pure water which is exposed to the atmosphere, we assume that the total concentration of carbonic acid in pure water is equal to the sum of dissolved carbon dioxide and ...
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Regarding salt hydrolysis of weak acid - weak base salt

For a salt made from a weak acid and weak base, say $\ce{NH4CN}$, my textbook represented hydrolysis at equilibrium by this reaction: $$\ce{NH4+ + CN- +H2O<=>NH3 + HCN}\\\text{ }\text{ }\text{...
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pH scale at various temperatures

I am an electrician apprentice in charge of a large number of pH-sensors/transmitters at a power plant and chemical plant. I do all the pH-instrumentation related maintenance, calibration, adjustments ...
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Why is aqueous solution of lauyl glucoside alkaline?

What is the reaction of dissociation of lauryl glucoside? It's aqueous solution pH is much higher than 7, it's definately alkaline. Why is that? It's nonionic surfactant and as far as I know it only ...
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Is lauryl glucoside stable in low pH?

I wish to use lauryl glucoside in the solution of citric acid. I tried to add it to 5% w/w solution of citric acid in water but after about 24h in the concoction which was previously clear I observed ...
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Weak acids compared to strong ones in pH > 7 solution

In the book of Molecular Cell Biology (Big Alberts) by Alberts, at page 46, it is stated that Acids—especially weak acids—will give up their protons more readily if the concentration of > H3O+ in ...
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Is it possible to make a solution of zinc oxide in a high school chemistry lab?

As part of my IB Chemistry curriculum, we are required to conduct our own experiment researching our own question. I'm in the preliminary research phase and wanted to conduct an experiment looking at ...
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194 views

How to make acetic acid more volatile so that it can be removed by vigorous aeration of an acetic acid-water mixture? [closed]

I want to remove acetic acid from a mixture of acetic acid and water by aeration. The concentration of acetic acid is 200 ppm (mg/L). The pH of the water is more than 5. I want to reduce the acetic ...
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Modelling pH as function of time and position

I already posted this on the Engineering Stack Exchange under Chemical Engineering as I don't know where it's a better fit. I have a system whose initial state consists of three different sections ...
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pH vs Volume curve [closed]

$100 \mathrm{mL}$ of $0.1 \mathrm{M-} \mathrm{HCl}$ is taken in a beaker and to it $100 \mathrm{mL}$ of $0.1 \mathrm{M-} \mathrm{NaOH}$ is added in steps of $2 \mathrm{mL}$ and the $\mathrm{pH}$ is ...
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Why are there no alkaline foods?

It takes some work to find a list of the actual pH of various foods. (Searches are confounded by a popular "alkaline diet" theory that the pH effect on a human body of consuming various ...
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Is an aqueous solution of potassium bicarbonate acidic or basic in nature?

The following is the definition of an acid salt according to my textbook: The salts formed by the partial replacement of the replaceable hydrogen atoms (H+ ions) of an acid molecule by a metallic or ...
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54 views

How to change pH of CuSO4?

I'm currently very desperate to know this. I'm doing an experiment about adsorption/chelation of Cu ions in CuSO4 using banana peels using the UV-Visible spectroscopy. How do I change the pH of 0.1M ...
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What has happened with the pH-meter?

The glass sensor has became red inside like something melted. I stored it in a liquid with pH that mentioned in the manual. What is that and why could that happen, how often that happens with pH-...
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Why is sodium bicarbonate added to lower the pH? [closed]

I use salicylaldehyde, chloroacetic acid and sodium hydroxide for the synthesis of o-formylphenoxyacetic acid. In the procedure it is written that after the reaction I need to add sodium bicarbonate ...
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How does a change in pH affect the colour of a leuco dye in a thermal paper?

I am investigating the way that a leuco dye is released in thermal paper once heated. I have understood that leuco dyes, when in their colourless state are encapsulated in an acid developer in the ...
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1answer
73 views

Why are amino acids least soluble at isoelectric point?

At isoelectric point amino acids exist as zwitterions. As a molecule it is electrically neutral, but still has a positive and a negative charge. Then why are amino acids still least soluble at ...
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1answer
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Find volume of ammonia gas required to prepare a solution of given pH [closed]

Calculate the volume of gaseous ammonia $(K_\mathrm{b} = \pu{1.8E-5})$ to dissolve (at NTP) in $\pu{100 mL}$ of water in order to obtain a solution with $\mathrm{pH} = 11.0.$ Consider volume variation ...
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Common Ion Effect - Ionic Equilibrium

Question In which of the aqueous solutions of the following, dissociation of $\ce{NH4OH}$ will be minimum? A) $\ce{NaOH}$ B) $\ce{H2O}$ C) $\ce{NH4Cl}$ D) $\ce{NaCl}$ My Thoughts My book says that ...
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Which one of the two is the stronger base: methoxide ion or hydroxide ion? [duplicate]

If we consider the experimentally determined pka values, it looks like hydroxide ion should be the right answer but in many books it has been mentioned that all alcohols are less acidic than water ...
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6463-T6 aluminum oxidation and role of water and ethanol vapor

Our issue...in a nutshell: We use 6463-T6 aluminum as a sampling "cell" for analysis of water and ethanol vapor mixtures in both wet and dry gas variations. As I understand it, the ...
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How to calculate the pH of solutions of amphoteric salts? [duplicate]

I've been trying to understand how to calculate the pH of solutions of amphoteric salts, but I just can't figure it out. So, I've seen that it is commonly explained like this (example for a solution ...
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Finding the pH of the resultant solution when a pH1 solution mixed with a pH2 solution [closed]

I want to know that is it possible that a $\mathrm{pH_1}$ solution mixed with a $\mathrm{pH_2}$ solution and the mixture would be less than $\mathrm{pH_1}$? Is it possible that the result has a lower $...
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Help with determining concentration of magnesium hydroxide for a specific pH level

This seems like such an obvious and elementary-level question for someone who has taken high school chemistry, but yet I'm having a difficult time solving it. I need to find the right amount of $\ce{...
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Can we determine pH of liquid at home without pH-meter or litmus paper? [closed]

Are there alternative ways to determine $\mathrm{pH}$ of a liquid without using $\mathrm{pH}$-meter or litmus paper? In case if we didn't cook the liquid ourselves and don't know concentration of acid ...
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1answer
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What the difference in data if calibrate pH-meter with 2 and 3 solutions? [closed]

pH-meter (12 bucks one) can be calibrated with 2 different solutions (let's say 4.0 and 6.86), but as an option 3 can be used (4.0, 6.86 and 9.18). If I use 2 instead of 3, what error I'm going to get....
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Calculating dissociation constant at different pKw values

What are the standard approaches to calculating how dissociation constants for acids and bases, $\mathrm{p}K_\mathrm{a}$ and $\mathrm{p}K_\mathrm{b}$, change as the ionic product of water, $\mathrm{p}...
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42 views

Does Genistein remain in resonance stabilised form in physiological pH or acidic pH? [closed]

As a follow up, does the Carbonyl group at 4 position group get deprotonated or Hydroxyl group at 5 position get deprotonated? How does the resonance structure look? I have been looking through ...
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When is a buffer solution considered efficient?

By this I mean what is the rigorous definition of a buffer solution? I know that a buffer is a solution able to resist changes of $\mathrm{pH}$, but how much resistance to $\mathrm{pH}$ does a ...
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How much NaOH I have to add to increase pH?

I'm stuck in solving this problem. I have two solution of $\pu{5 M}$ $\ce{H2SO4}$ that needs two consequential $\mathrm{pH}$ increasing: the first from the natural $\mathrm{pH}$ of $\pu{5 M}$ $\ce{...
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Is it possible to graph the equivalence of p[Cu²⁺] with pH?

In no way I am a chemistry major, so please forgive me if my question seems stupid. I just need a way to find the "equivalent $\mathrm{pH}$" of $\mathrm p[\ce{Cu^2+}]$ if that makes any sense to you. ...
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Is pK_{In} = pH at equivalence point still true for weak basic organic indicators?

I am reading Ostwald Theory of Titration which says that indicators are organic weak acids or bases. To prove the relation that $\mathrm{p}K_\mathrm{In} = \mathrm{pH}$, the textbook uses the following ...
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What actually happens in strong acid- weak base reactions?

I'm going back through my notes from a chemistry class, which I did well in despite not having a very good conceptual understanding, in order to hopefully develop that understanding, but there's ...
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How does pH depend on temperature, when taking into account volume expansion?

Since autodissociation of water is endothermic, increasing the temperature will drive the following equilibrium to the right, which has the effect of increasing $[\ce{H+}]$: $$\ce{H2O <=> H+ + ...
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Calculating the biological standard potential

I have an electrochemical cell with following overall reaction: $$\ce{5 Sn^4+ + 2 Mn^2+ + 8 H2O <=> 5 Sn^2+ + 2 MnO4- + 16 H+}$$ I have defined the half reactions as: $$ \begin{align} \ce{Sn^...
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1.0 g of AlCl3 is added to 100.0 ml of water. What would be the resulting pH?

$1.0\ \mathrm g$ of $\ce{AlCl3}$ is added to $100.0\ \mathrm{ml}$ of water. What would be the resulting pH? I think the answer may be $4.022$ but I'm not certain. The reaction wasn't provided but I ...
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Calculating the pH given number of moles of HI and 500. ml of water

Shouldn't we also add the volume of the HI to the volume of the water (500mL) when we calculate the molarity? My book simply divided the number of mol by 500 mL.
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Why does pouring carbonated beverages onto fruit cause them to fizz? [closed]

I have noticed that making mimosas, the champagne fizzes more than just pouring it into a flute. Likewise, pouring beer onto citrus fruit or strawberries fizzes a lot. My theory is that the pH drop ...
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Why is HCl the acid of choice for swimming pools?

Why is muriatic acid the go to acid to put into pools? Does it work better than nitric acid, sulfuric acid, or another strong acid? I mean they all will add the same amount of H+ right? Note, we use ...
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What is the correct pH value of weak and strong alkalis? [closed]

In the book titled fundamental chemistry for Cambridge O level, it states at page 149, Ammonia solution with a pH of 11.1 is a weak alkali and that's why it shows much lower conductivity of 0.50 ...
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Calculating ratio of conjugate base and acid when pH and pKa are given

Buffer solutions are used by biological mammalian systems to maintain the $\mathrm{pH}$ of blood plasma within a narrow range. In these systems, the compound from which this solution is obtained is $\...
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The pH of a drop of water containing ammonia

Presented with the following equations: What would the $\mathrm{pH}$ of a drop of water be, while in equilibrium with $\ce{NH3(g)}$ at a concentration of $\pu{150 ppb}$? $$\ce{NH3_{(g)} + H2O_{(l)} &...
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Finding new pH after adding potassium hydroxide to citrate buffer

Calculate the $\mathrm{pH}$ change of citrate buffer containing $\pu{10.26 mmol}$ of citric acid and $\pu{6.98 mmol}$ citrate caused by adding $\pu{4.72 mmol}$ of potassium hydroxide. $\mathrm{p}K_\...
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Strong Base and weak acid reaction problem

I got the above problem correct by setting up the net ionic equation and finding the limiting reactant. I found that there were 0.01076 moles of NaOH left, and then calculated it's molarity which led ...
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How does the pKa of a neutral molecule inform the protonation state of its positively charged molecule?

Let's say we have some neutral molecule A and its protonated form, A+. The pKa of molecule A is known, but we do not know the pKa of molecule A+. Can the pKa of molecule A+ be determined only knowing ...
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Calculating the pH of a sodium phosphate solution [closed]

I have the following question in a chemistry homework: Calculate the $\mathrm{pH}$ of a solution made by dissolving $\pu{113 g}$ of sodium phosphate in enough water to make a solution with a final ...
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Order of adding reactants on growth of Cu

I am reading the following paper which details the steps to control growth of Copper. They fabricate Copper powders from $\ce{CuNO3, NaOH, and C6H8O6}$. Specifically, in this paper they add the sodium ...

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