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).
2,613
questions
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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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0answers
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How to find out equivalent to about 2 mg of sodium in sodium metabisulphite? [closed]
How to find out equivalent to 2mg of sodium in sodium metabisulphite? Please help to find out this problem.
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1answer
32 views
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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2answers
46 views
Reaction of phosphorous acid (H3PO3) and potassium hydroxide (KOH)
For the reaction of phosphorous acid ($\ce{H3PO3}$) and potassium
hydroxide ($\ce{KOH}$), write (a) the balanced molecular equation
and (b) the net ionic equation. Note that phosphorous acid is
a ...
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0answers
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Are dehydrator sheets discolored by tomatoes safe? [closed]
I inherited an older tray-style food dehydrator along with dehydrator sheets from the 90s. I am not sure what the sheets I received are made of, but they became discolored by the tomatoes I dehydrated....
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comparision between basic nature of CH3O- and -OH
when comparing the basic nature of $CH_3O^-$ and that of $OH^-$. I found two arguments. one favoring the more basic nature of $CH_3O^-$ and the other favoring the basic nature of $OH^-$. so which of ...
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1answer
35 views
Reaction of Alkane RCOOH with KOH [closed]
The question is as follows:
As much as 4.4 g of organic acid RCOOH is precisely neutralized by 200mL KOH 0.125 M.The molecular formula for the organic acid and the name of the acid compound with one ...
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1answer
27 views
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:
$$\ce{NH4+ + CN- +H2O<=>NH3 + HCN}\\\text{ }\text{ }\text{...
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1answer
44 views
Will a salt dissociate completely in water to give free ions?
I was reading salt hydrolysis of a salt made from strong acid and weak base. I came across the hydrolysis of $\ce{NH_4Cl}$. These reactions were mentioned
$$\ce{NH_4Cl + H_2O<=>NH_3 + HCl \tag{...
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1answer
22 views
How Is This Acid Base Map Established?
In the Acid-base map -shown below- each line denoted as an isohydric line shows the pairs of $ PCO_{2}$ & $ [HCO_{3}^{-}] $ that give a certain $ pH $. So each line connects the values of $ PCO_{2}...
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What the difference between these health-wise safe active ingredients? [closed]
I'm not a chemist. I just read different articles and try to make sense to myself.
As I understood Hypochlorous Acid is naturally produced by our white blood cells. Therefore, it's safe (health-wise) ...
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0answers
24 views
Is it OK to dispose of potassium hydrogen phthalate into the sewer system?
I have been using potassium hydrogen phthalate (KHP) for creating primary standards. I have looked into the Flinn catalog, and the disposal consideration is classified as "organic acids, must be ...
1
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0answers
37 views
What makes concentrated aqueous solutions of aluminium nitrate and aluminium chloride suitable to dissolve noble metals, specifically gold? [closed]
Aluminium nitrate is a strong oxidising agent and aluminium chloride acts as a Lewis acid. Also these solutions are claimed to have the abilities of aqua regia and therefore can dissolve noble metals.
...
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1answer
34 views
Does the acid dissociation constant takes hydrogen ions from water into account?
For the dissociation of a weak acid:
$$\ce{HA(aq)<=>H+ + A-}$$
To calculate $\mathrm{pH}$ of a weak acid, we use the expression: $$K_\mathrm{a}=\ce{\frac{[H+] [A-]}{HA}}$$
The $\ce{[H+]}$ has ...
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0answers
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How concentrated does sulfuric acid need to be for nitric acid synthesis (H2SO4 + nitrate salt distillation)?
So I have a home lab setup and recently found myself in need of some nitric acid. I could just buy some, but I thought it would be a useful exercise to make my own. I have plenty of nitrate salts ...
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0answers
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This question is about Acids and bases [closed]
what does the underlined stuff even mean. this is an acid base topic and it is about calculating dissociation constant ka and kb. the thing that is confusing me is the underlined sentence. I don't get ...
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2answers
40 views
Are burns from Lye or Potash that bad?
I read that the chemicals potassium hydroxide and sodium hydroxide are extremely corrosive and will cause severe burns but I also see videos of people saying that if you get lye on you, then just wash ...
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0answers
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titration - phenolphthalein
Phenolphthalein was the indicator used in the titration video. It is an appropriate indicator for the reaction because? This was in strong base/strong acid.
a. it's colour change from colourless to ...
0
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2answers
56 views
Unusual Titration Curve Explanation
From Costanzo's Physiology book in Acid-Base Physiology chapter, this titration curve of a weak acid ($\ce{HA}$), in the context of discussing buffers is provided:
What confused me is that in this ...
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2answers
38 views
What concentration of HCl is safe to smell? [closed]
I want to give students the chance to gently waft and smell HCl.
What concentration would be considered safe for a once-off single waft and smell ?
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1answer
33 views
How does an acid dissociate in water [duplicate]
I read somewhere that hydrogen cation combines with water to form hydronium ion. I also read it combines with various water molecules. Can someone please explain?
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1answer
50 views
O-formyl benzoic acid or p- formyl benzoic acid. Which is more acidic?
As far as I can think, the ortho effect comes into play which makes o-formyl benzoic acid more acidic.
But according to some, due to Hydrogen bonding between aldehyde and carboxylic group, hydrogen ...
1
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1answer
82 views
Is HCl a lewis base?
Cl in HCl has three lone pairs of electrons. So it can donate a lone pair and thus become a lewis base. Right? Just like water is called a lewis base because oxygen has 2 lone pairs and can donate a ...
0
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1answer
22 views
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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1answer
36 views
Dissociation constant for Indicators
So I came across a question which asked to calculate the $\mathrm{pH}$ at which an indicator of given $\mathrm{K_{a}}$ would change colour. The solution was given in the following way
Since when the ...
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votes
1answer
50 views
How does chromium behave in a carbonate solution? [closed]
I'm wondering how chromium (as a metal or as a salt) behaves in a concentrated carbonate solution. Will it form any, one or several carbonate specie(s)? Will the metal solubilize? How does it affect ...
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votes
1answer
51 views
Why are these H the most acidic?
I don't quite understand why these two hydrogens are the most acidic. From a hybridization perspective, these are connected to a $\mathrm{sp^3}$ carbon (I thought the more s character, the more acidic)...
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3answers
196 views
What does *oxidizing* have to do with *hydrogen*? [closed]
An oxidizing acid is a Brønsted acid that is a strong oxidizing
agent. All Brønsted acids can act as oxidizing agents, because the
acidic proton can be reduced to hydrogen gas.
(source: Wikipedia)
...
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0answers
22 views
Acidity of carboxylic acids
is there a reliable database with the pKa of halogenated carboxylic acids? I am also looking for the pKa of ethanoic acid substituted with other electronegative elements (like sulfur and oxygen).
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0answers
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When the basicity of hydroxides of group 1A and group 2A increase down the group, why do we have NaOH as the strongest base? [duplicate]
When the basicity of hydroxides of group 1A and group 2A increase down the group, why do we have $\ce{NaOH}$ as the strongest base located at the top of group 1A? Shouldn't, if the trend is followed, ...
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1answer
35 views
Effect on acidity of benzene due to electron withdrawing groups
With respect to the compounds I–V, choose the correct statement(s).
Compound II becomes more acidic when it has a $\ce{-NO2}$ substituent.
The acidity of compounds follows the order I > IV > V &...
2
votes
1answer
146 views
Fish Fertilizer acid / base reactions
Hi Everyone new to chemistry and learning lots but I had a question that I am having trouble working out.
I work for a vegetable grower and we make our own fertilizer.
My question is around the fish ...
1
vote
2answers
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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votes
1answer
22 views
Hydrogen and Hydrogen ion
Is it correct that a hydrogen atom only has 1 electron and 1 proton since the atomic mass is 1?
Also, is the hydrogen ion composed of a single proton and no electrons?
In an ionization process we know ...
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votes
1answer
27 views
Is Cu stable as Cu(H2O)2+ for determination on MP-AES? [closed]
I have an unknown sample of mineral which I need to dissolve in nitric acid. I need to analyze $\ce{Cu}$ from it on MP-AES. Do I need to add $\pu{1ml}$ of $\ce{HCl}$ to stabilize $\ce{Cu}$, or it is ...
2
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0answers
48 views
Comparing basic strength of phosphorus trichloride and phosphorus trifluoride
I need to compare the Lewis basic strength of trihalides of phosphorus
My thoughts :
Since fluorine is more electronegative, the percentage of $\mathrm s$-character in $\ce{P-F}$ bonds will be lower, ...
4
votes
1answer
81 views
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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1answer
21 views
Acids and Bases (Spectator Ions Identification)
In an acid reaction with water, or other solvents, how do we know which atom(s) from a compound reacted with that solvent are the spectator ions? Are they the ones soluble in the solvent?
Is the way ...
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0answers
37 views
Writing water as a reactant in acid/base dissociation (Brønsted Lowry)?
The dissociation of $\ce{HCl}$ in water is written as:
$$\ce{HCl (aq) -> H+ (aq) + Cl- (aq)} \tag{1}$$
Sometimes we also include $\ce{H2O}$ as a reactant to stress the fact that the protons are not ...
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3answers
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The Curious Case of the equivalent weight
Please read the reference points given at the end.
I understand the following about equivalent weight. Firstly it is given by,
$Equivalent\:Weight= \frac{Molar\:Weight}{Valence\:Factor}$
And secondly, ...
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0answers
32 views
Arrhenius acids and bases
According to the Arrhenius definition of acids:
An Arrhenius acid is any species that increases the concentration of
hydrogen ions in its aqueous solution.
Hydrogen Chloride gas ionises in water to ...
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0answers
18 views
IUPAC salt definition makes bases be classified as salts? [duplicate]
The IUPAC salt definition is: "A chemical compound consisting of an assembly of cations and anions" (Compendium of Chemical Terminology Gold Book, Version 2.2.3, 2014)
So it means that a ...
0
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1answer
49 views
Why isn't auto ionisation of water considered when we find the pH during salt hydrolysis?
$\ce{H+}$ concentration from the auto-ionisation of water is $10^{-7}$
If we have $\ce{HA}$ as weak acid and $\ce{BOH}$ as weak base having $\mathrm pK_\mathrm{a} = 3.2$ and $\mathrm pK_\mathrm{b} =3....
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2answers
47 views
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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0answers
180 views
What are acid/base sensitive groups?
My textbook says that Clemmensen Reduction cannot take place in the presence of an acid-sensitive group and the Wolf Kishner reaction won't happen in the presence of a base sensitive group, citing $\...
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0answers
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Why can't Grignard reagents react like Organolithium does (with acids)?
I'd read yesterday that Grignard reagents can't give ketones on reaction with carboxylic acids. It is because of the fact that Grignard reagent is a "super-base", and it will deprotonate the ...
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2answers
123 views
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 ...
0
votes
1answer
69 views
Why is aniline more basic than pyrrole?
In a question asking to compare the basicity of pyrrole and aniline, the explanation given for aniline being more basic than pyrrole was as follows:
Basicity depends on the availability of lone pair ...
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votes
2answers
57 views
Reaction of copper with nitric acid [duplicate]
When copper reacts with dilute nitric acid,
$$\ce{3Cu + 8HNO3 -> 3Cu(NO3)2 + 2NO +4H2O}$$
while with concentrated nitric acid,
$$\ce{Cu + 4HNO3 -> Cu(NO3)2 + 2NO2 + 2H2O}$$
As we see that with ...
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0answers
19 views
How does concentration of H3O effect the concentration of OH [duplicate]
I know that [H+][OH-] will always equal 10^-14 in 25c water, however, I would like to know why that is, like if there is an extremely small amount of both H+ and OH- in the water how would increasing ...
