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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32 views

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?

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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How to determine the pH of a given aqueous solution of HCl of unknown concentration using double titration? [duplicate]

I currently have a practical to do for school in which I have to to determine the pH of a given aqueous solution of HCl of unknown concentration. My teacher mentioned something about double titration ...
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2answers
63 views

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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4answers
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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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2answers
120 views

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
95 views

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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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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1answer
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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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187 views

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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2answers
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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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1answer
108 views

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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2answers
243 views

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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27 views

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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1answer
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How to calculate the amount of water required to increase the pH of a solution from 2.1 to 4? [closed]

After working out the problem with certain approximation of considering the initial pH=2, my answer came out to be around 1 litre of water. But the correct answer is 79 litres of water. Can anyone ...
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2answers
73 views

Change in concentration when acids are diluted

I came across this formula to calculate the resultant [H]+ concentration when two weak acids are mixed (Both acids of equal volumes are mixed together). The only problem i have with this is that, we ...
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1answer
122 views

How to calculate bicarbonate and carbonate from total alkalinity [closed]

It's been a long time since I did my chemistry classes and I'm currently trying to analyze groundwater samples for hydrogeology purposes. I would like to evaluate carbonate and bicarbonate ...
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Total Dissolved Solids and Alkalinity [closed]

I need to calculate total dissolved solids (TDS) of various groundwater samples from chemical analyzes. I have concentrations of ions/molecules in mg/L. I’ve found various formulas to calculate TDS ...
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1answer
46 views

Finding the volume needed to make a new pH

In the titration of 20.00 mL of 0.500 M HCl by 0.500 M NaOH, calculate the volume of 0.500 M NaOH required to reach a pH of 2.0. I have tried to change the 20.00 mL into the amount of substance (0.01 ...
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Is it possible to measure pH without physically coming into contact with a solution?

I've been researching ocean acidification, and the way that ocean pH is typically measured is by using sensors placed throughout all of the oceans. This is costly and time-consuming, and being able to ...
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31 views

How to add components in visual MINTEQ

I need to figure out speciation of a mixture of metal nitrates and chloroplatinic acid. I am using visual MINTEQ to do this. But platinum ion is not there in the visual MINTEQ component list. I need ...
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Why is the experimental pH of vinegar (acetic acid) so much higher than expected?

I bought some sodium hydroxide on Amazon and went about titrating solutions I make with it. As I'm an amateur chemist at home, I have limited tools. A pad of paper, some 5% acetic acid vinegar, and ...
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1answer
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What does the value of the pH meter mean when there aren't any hydronium ions in the substance being tested? [closed]

What does the value of the pH meter mean when there aren't any hydronium ions in the substance being tested? How does the pH meter show a value which fluctuates as non-aqueous solvents are being ...
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3answers
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pH implications of redox balancing half reaction method

I have seen similar questions, but I’m asking a new question as far as I know. Why is water instead of hydroxide ions used to balance oxygen atoms in redox half equations? asks about using hydroxide ...
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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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43 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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55 views

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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48 views

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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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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1answer
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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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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
41 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
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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
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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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