Questions tagged [acid-base]
This tag should be applied to questions concerning acid and base reactions. An acid is capable of donating a hydron/ proton (Brønsted acid) or capable of forming a covalent bond with an electron pair (Lewis acid). A base on the other hand is a chemical species/ molecular entity having an available pair of electrons capable of forming a covalent bond with a hydron/ proton (Brønsted base) or with the vacant orbital of some other species (Lewis base).
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Number of significant figures to use in reporting the concentration of the titrand in acid-base titration [closed]
If you perform an acid-base titration yourself, how do you determine the number of significant figures to use when reporting on the concentration of the titrand?
Assume you perform seven titration ...
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Why do H and Li bond so differently with a hydroxide?
I am sure I am asking a very basic question but before coming here, I have made multiple attempts to find an answer elsewhere. Or maybe I am simply asking the wrong question, in some sense. If someone ...
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Exact calculation of pH of diprotic acid plus strong base
Another post has an excellent "exact" calculation for the [H+] (or pH) of a generic diprotic acid dissociating in water.
Combining acid dissociation constants to determine pH of diprotic ...
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Acid dissociation of two polar liquids
I was thinking in a case where the solute and solvent are two different polar liquids and according to Does the acidity constant depend on the solvent? the constant of dissociation change with the ...
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pH and degree of dissociation of drugs
I have a doubt, i hope not so stupid.
Suppose we consider a buffer solution of acetic acid/acetate at pH = pKa = 4.76 and we add aspirin (pKa = 3.5): given that the pH of the solution is higher than ...
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Acidity of alcohols and basicity of amines
I've been studying acids and bases in organic chemistry. My textbook says that alcohols are very weak acids, therefore they cannot react with strong bases. the conclusion i formed from this was: very ...
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The edge case of an edge case: Vapor emissions of the descaling agent Sulfamic acid
I am wondering about the following scenario:
What happens if ready bought sulfamic acid descaling (usually 15% cont. + $\ce{H2O}$) is vaporized or at least steam develops while very briefly descaling ...
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Acidic strength of nitrophenols
I've seen the pKa values of Nitrophenol as follows:-
pKa of o-nitrophenol= 7.23
pKa of p-nitrohenol= 7.14
so p-nitrophenol is more acidic than p-nitrophenol
But both phenoxide ions are stabilized ...
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Acidic strength order among hydroxytetralones [closed]
I can understand in 1 the conjugate base has more stability for better resonance but in 2 and 3 the effect of resonance cannot be considered. How can we compare the inductive effect in such case?
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What is ionic reaction equation for reaction between carbon dioxide and limewater?
Write the ionic reaction equation for the reaction
\[\ce{Ca(OH)2(aq) + CO2(g) <=> CaCO3(s) + H2O(l)}.\]
I first wrote the complete ionic equation as such:
\[\ce{Ca^2+ + 2 OH^- + CO2 <=> ...
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Calculate the pH at the equilibrium point in an acetic acid sodium hydroxide titration
You perform a titration of $\ce{CH3COOH}$ with $\ce{NaOH}$. Let the original concentration of acetic acid be $\pu{0.2 M}$. The volumes of $\ce{CH3COOH}$ and $\ce{NaOH}$ are the same. Then the ...
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If Ethyne has the lowest C-H bond length (highest C-H bond energy) compared to Ethane and Ethene, why is it the most acidic? [duplicate]
I am not an expert in chemistry, but these are the few facts I know from Standard XII chemistry books (these facts could be wrong or incomplete or modified by now).
Facts I know -
Ethane has 'sp$^3$' ...
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Does hand dishwashing liquid degrease as well as add "grease"?
When preparing a copper etching plate for etching, it must be degreased completely before putting on the etching ground. Otherwise the acid may "bite" through the ground ("foul biting&...
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Calculating equilibrium constant for a general acid base reaction
I am trying to find the equilibrium value for different acid-base reactions. I have understood that when an acid and base are in an aqueous solution, many different reactions will occur. By combining ...
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How would you use henderson equation to calculate the pH of a solution containing multiple different acids, such as carbonic acid and acetic acid? [closed]
I would like to know if it is possible to use the Henderson equation to calculate the pH of a solution containing more than one kind of weak acid.
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how to neutralize stannous chloride (50ml) to make it safe for disposal
I made a small quantity of stannous chloride by dissolving tin in muriatic acid - I would like to neutralize it for safe disposal - will mixing it with soda bicarbonate dissolved in water accomplish ...
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Effect of pH on solubility (Lehninger's Principles)
The following problem is found in Lehninger's 8 Ed.:
I understand the reasoning in the problem statement: in a basic solution, more of the acid dissociates, and this dissolves, since the ionized form ...
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What is the charge of amino acid in alkaline conditions?
This problem refers to the protein buffer in a living system.
"If the blood pH becomes alkaline, there is a release of a proton from the
$\ce{NH3+}$ ion, which takes the $\ce{NH2}$ form."
I ...
user131254
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"Cleaning" of HNO3 solution using distillation
In many industries, pickling baths are common. These are 10 cubic meter baths containing acid baths that metal components are dipped into prior to surface treatment. When the metals are dipped, some ...
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Colour changing Lipstick
I have bought a colour changing lipstick with the colour Phloxine B.(Other ingredients, see below...)
Normally this colour changes to pink at pH 5.
So this means on skin it changes its colour because ...
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1
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Examples of stable organic cations [closed]
What are examples of organic cations that are stable at room temperature, can be isolated and that cannot be easily deprotonated by $\ce{NaOH}$? My only guess are various compounds with tetravalent ...
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Do all bases release OH-? [closed]
Do all bases release OH-? Do all bases have the ability to receive an H+ ion? As an example, CaCO3 is a base but it doesn't release OH- ions.
PS. I am a high school student
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Even in an acidic solution with a pH equal to 0, there are only 1 mol/L H3O+ ions, while there are approx. 54 mol/L water molecules
I find this sentence in my high school chemistry book to be confusing:
"Even in an acidic solution with a pH equal to 0, there are only 1 mol/L H3O+ ions, while there are approx. 54 mol/L water ...
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How to find a method of determining whether an acid is strong or weak given only a formula? [closed]
I know that strong acids dissociate completely in water, and weak acids dissociate only partially. I searched for a method for finding if an acid is strong or weak given its formula, but the answer ...
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Why does my sand dissolve in citric acid?
I soaked and washed white Darice decorative sand in distilled water. I added food-grade citric acid to different distilled water, then I sprinkled in a few grains of the sand. The sand bubbled and ...
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What's the pH of a solution knowing only pKa, mass and volume? (no molecular mass known)
Is it possible to calculate the pH of a given solution knowing only the pKa (but not the structure of the acid, i. e. its molecular mass), its mass and the volume of the solution? E. g. What is the pH ...
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What determines strength of nucleophile--Polarisability or Electron density
My understanding is that nucleophiles are lewis bases. Apparently nucleophile and base strength are not the same though. I thought Nu strength/Base strength is determined by how well it can donate an ...
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Which one is more Bronsted basic?
pyrrole anion vs imidazole anion
I at first thought it was the right one because it has 2 lone pairs so I would assume it would have more affinity towards hydrogen protons. However, the resonance ...
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Calculating rate constant for reaction between potassium permanganate and oxalic acid
I'm writing a lab report investigating the effects of temperature on the rate constant in the reaction between potassium permanganate and oxalic acid. For my practical I've measured the time of colour ...
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Protonation in acid-catalyzed nucleophilic attack of alcohol on carbonyl
When studying acid-catalyzed nucleophilic attack of alcohol on carbonyl, I got puzzled by the first protonation step. In textbooks, they often show that the first step is to protonate the carbonyl ...
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Safe disposal of hydrochloric acid
We recently bought a home and found about 2 litres of hydrochloric acid 20% (also known as muriatic acid) that was used to manage acidity in a swimming pool that no longer exists. I would like to ...
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When NaOH ionizes in water, does the OH– react with the water molecules or with the hydronium ions from the dissociation of water?
NaOH in water becomes $\ce{Na+}$ and $\ce{OH-}$ ions. If it's a Bronsted Lowry base then the $\ce{OH-}$ ions will take $\ce{H+}$. But FROM where exactly - from the water molecules or from the ...
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Does temperature affect ionic strength?
Hello I apologize if this is a dumb question but if I have a phosphate buffer made up of Na2HPO4 and NaH2PO4 and I gradually increase the temperature (lets say 10,20,30,40,50) what would happen to the ...
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Measuring [A-]/[HA-] with Buffer and Indicator
I'm very confused on how to calculate the [A-]/[HA] value, given the fact that my dilution series uses buffers at various pH values with the same indicator (supplied at the same concentration to each ...
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Why is phosphine more acidic than ethylene?
Shouldn't ethylene should be more acidic? It has a C=C bond, so the density of electron cloud would be higher in the areas of the double bond while the C-H single bond have way less electron density. ...
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Why do stable covalent compounds react with water [closed]
I am curious why a discrete covalent molecular substance, say CO2, would react with water to form an acid, what happens in such a reaction? I'm assuming it has something to do with disassociated ions ...
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Is ethylene more acidic than phosphine?
Yeah, it's straight forward. Is CH2=CH2 more acidic than PH3 or not? Why so or why not?
Any help or hint would be amazing. Thanks!
PS: I think ethylene should be more acidic. It has a carbon-carbon ...
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Why can't the product of an acid reacting with water react with water itself and produce OH-?
Why can't the product of an acid reacting with water react with water and produce $\ce{OH-}$?
Take the reaction below as an example:
$$\ce{H2CO3(aq) + H2O(l) <=> HCO3-(aq) + H3O+(aq)}$$
$$\ce{...
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Predict who is the acid and who is the base in an acid-base reaction using pKa
In my book (Bruice) it is specified how it is possible to compare the pKa of two substances to understand who acts as an acid and who as a base. Here's the example in the book:
$\ce{NH3 + H2O}$.
$\...
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Why is the inductive effect possible?
Firstly, I must preface that I am a Biology student. To elaborate my question, I was looking for the reason why carboxylic acids are more acidic than alcohols, despite both compounds containing —OH ...
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Should nitric acid be classified as a strong acid? Does it completely dissociate in water?
By definition, a strong acid must completely ionize in aqueous solution. However, in order to completely dissociate in water, strong acids must be more acidic than a hydronium ion and hence have a pKa ...
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Experimental evidence for zwitterions
If I have a diprotic acid that is +1 positively charged in its fully protonated state, I can figure out the apparent equilibrium constants by titration with base. The net charge will be neutral after ...
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Buffer solution of NaH2PO4 and Na2HPO4
We have this exercise without solutions
From a 0.2 M $\ce{NaH2PO4}$ solution and a 0.2 M $\ce{Na2HPO4}$ solution, a buffer
solution with pH = 6.8 is to be prepared. The total concentration of
$\ce{...
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Why don't serine and threonine have a 3rd pKa
Serine and threonine both have an extra OH functional group and hence they should be able to dissociate when the pH gets high enough. However multiple amino acid pH charts do not show the 3rd pKa of ...
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Is an aqueous solution of lithium superoxide basic or neutral? [closed]
Is the aqueous solution of lithium superoxide basic or neutral?
I know that $\ce{Li}$ is a metal, thus its oxide ($\ce{Li2O}$) produces base in reaction with water.
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Why is water present in "pure" nitric acid and RFNA and WFNA?
Various types of nitric acid have been used in rocket fuels as oxidisers (RFNA is red fuming nitric acid, WFNA is white fuming nitric acid) as they are often hypergolic with a wide variety of fuels.
...
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What is the best chemical for cleaning fossils and rocks [closed]
I am new to fossil collecting and would like to know what chemical is best for cleaning fossils and rocks of clay deposits. Specific acids/bases
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Why doesn't the volume of NH3 = 325 ml in this problem? [closed]
I'm struggling with the problem below, and don't understand why
A buffer solution with pH = 9.0 is to be prepared from a 0.2 M ammonia
solution and a 0.15 M $\ce{HCl}$ solution. The sum of the molar
...
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Why is the precipitate formed after dissolving trimagnesium dicitrate anhydrate?
In my research I try to prepare trimagnesium dicitrate aqueous solution. Initially it stays clear, but after some time white insoluble precipitate is formed. Initial pH was about 4,5-5,0. If pH is ...
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How to find the deprotonation percentage of an acid?
Given is an aqueous solution of mandelic acid (M = 152.2 g/mol; $pK_a$ = 3.4) with a molar concentration of 0.3 mol/ liter. A $\mathrm{pH}$ value of $2$ is measured for the aqueous mandelic acid ...
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