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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5
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1answer
151 views

Is there any notion of pH out of solution?

For example, could one define a $\mathrm{pH}$ for pure acetic acid? It's a weak acid in water, but if someone handed you $1~\mathrm L$ of pure acetic acid, what would its $\mathrm{pH}$ be?
2
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1answer
626 views

Chalcogens' hydrides as acids?

I've noticed that chalcogens never form binary acids, and instead end up like water, with very little acidity. Why is this? Or am I wrong and there's a counterexample, if so please give it.
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2answers
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Do hydrogen halides (HX) form strong or weak acids?

I know that when dissolved in water, hydrogen halides ($\ce{H-X}$), become acids. I know that $\ce{HF}$ forms a weak acid, but can it be generalized that all $\ce{HX}$ acids do so?
9
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3answers
960 views

What is the word for how polyprotic an acid is?

What is the word to describe the number of acidic hydrogens an acid has? I am currently thinking something like "proticity", but I am not sure The use case world be for a table of things like this: <...
9
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2answers
9k views

Inductive vs resonance effects and the acidity of phenol

A lot of people rationalize the acidity of phenol by saying that resonance is responsible for much of phenol's acidity as opposed to aliphatic alcohols. However, this image suggests that in fact the ...
7
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2answers
4k views

Is there a difference in the reactions of a dilute acid and a concentrated acid?

All of the exams that I've sat so far, and the homework questions I've had, always ask for the reaction between a substance and a dilute acid. Is there a difference in the reaction between a dilute ...
6
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2answers
555 views

How is the trend of acidity in the sequence: phosphinic, phosphonic, phosphoric acid explained?

How is the trend of increasing $\mathrm{p}K_\mathrm{a}(1)$ value in the sequence: phosphinic $(1.24)$, phosphonic $(2.00)$, phosphoric acid $(2.21)$ explained (the image was taken from Housecroft ...
5
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1answer
1k views

Calculating pH in titration of monoprotic weak acid with strong base

$25.0\:\mathrm{ml}$ of $0.10\:\mathrm{M}$ $\ce{CH3COOH}$ is titrated with $0.10\:\mathrm{M}$ $\ce{NaOH}$. What is the $\mathrm{pH}$ after the addition of $30.0\:\mathrm{ml}$ $\ce{NaOH}$? In broad ...
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3answers
5k views

Halogen Oxyacid Trend (acid strength)

Why is $\ce{HClO4}$ more acidic than $\ce{HBrO4}$? But $\ce{HCl}$ is less acidic than $\ce{HBr}$? What determines the acidity? Is it the concentration of $\ce{H+}$? If so, how do these trends develop ...
3
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3answers
3k views

Inductive effect

In my teacher's power-point states that we must consider that inductive effect in $CH_{3}COOH$ exists because of the electron deficiency in $C$ (partial positive charge $\delta^{+}$) as a result of ...
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2answers
1k views

What is a “Strong” Acid?

If a reaction requires a "strong" acid - what does this mean? Does it mean any acid of a specific concentration or pH? Are only certain acids classed as "strong"? I have read on Wikipedia that it ...
2
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1answer
14k views

Why is buffer capacity at a maximum when the ratio of its components is 1? [duplicate]

A buffer consists of a weak acid and its salt or weak base and its salt. When the ratio of weak acid and its salt in a buffer (or the ration of weak base and its salt) is equal to 1, we say that the ...
6
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2answers
711 views

How to assess the strength of the acid?

Which is the stronger acid in the given pairs? $\ce{HClO3}$ and $\ce{HBrO3}$ $\ce{HClO2}$ and $\ce{HClO}$ $\ce{H2Se}$ and $\ce{H2S}$ given that the number of oxygen atoms is the same, ...
5
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1answer
17k views

Copper and hydrochloric acid

When hydrochloric acid is added to a sample of copper why does it look pink at first then form a pale blue solution ?
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2answers
10k views

Why will a strong acid neutralize as much base as a weak acid?

This is a simple concept that I can't seem to understand. Why will a strong acid neutralize as much base as a weak acid, if the acids are of the same volume and concentration? A strong acid will ...
2
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2answers
4k views

Ammonium Hydroxide Name

Why is an aqueous solution of $\ce{NH3}$ (ammonia) often referred to as $\ce{NH4OH}$? I know that dissolved ammonia gas reacts with water in the following equilibrium: $$\ce{NH3 + H2O <=> NH4+ +...
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2answers
8k views

Why is potassium phosphate KH2PO4 in this reaction?

This is a continuation of this question because the first thing that came in my mind is that why potassium phosphate in this reaction is $\ce{KH2PO4}$ and not $\ce{K3PO4}$? In the wikipedia article ...
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2answers
3k views

pH of ammonium acetate solution

I'm trying to calculate the pH of a 1M $\ce{NH_4CH_3COO}$. I know that I'll have these reactions: $\ce{NH_4CH_3COO <=> NH_4^+ + CH_3COO^-}$ $\ce{NH_4^+ <=> NH_3 + H^+}$ $\ce{CH_3COOH <=...
53
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4answers
183k views

Why add water first then acid?

From school, I remember a very important rule: first you need to pour the water and then the acid (when you need to mix them) not vice-versa. This is because otherwise the aсid becomes very hot and ...
33
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9answers
9k views

Would it be possible to destroy gold?

I'm a writer. I have a scenario in which a sizable amount of gold needs to be rendered unusable, preferably completely destroyed. I know an acid like aqua regia is able to dissolve gold, but would ...
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4answers
60k views

Why is salt needed when using vinegar to clean pennies?

Let's say you have a solution that is vinegar and it has salt (NaCl) dissolved in it. Then you place old dull pennies in it. Then you look at it 5 minutes later and the pennies are clean and looking ...
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4answers
3k views

What software can calculate aqueous solution equilibria?

What software is available out there to calculate the equilibrium in a set of reactions in aqueous solution? In particular, I'm interested in software general enough to simulate things like titration ...
14
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3answers
6k views

Why is magic acid a superacid?

The above is a representation of magic acid. The left part is the acid; the right part is the solvent. Why would this combination make for a particularly good acid? The left part looks like a ...
12
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4answers
15k views

Acidity order of nitrophenols

As in other posts I have seen and learnt that, if one is given four compounds, namely para-nitrophenol, ortho-nitrophenol, meta-nitrophenol and phenol and is told to arrange them in order of acidity, ...
10
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1answer
5k views

Why is picric acid more acidic than carbonic acid?

I just had a question in a test asking to compare the relative acidity of picric acid (TNP) and carbonic acid, $\ce{H2CO3}$ (not phenol). It turns out that TNP is more acidic. I have no idea why? Is ...
4
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2answers
69k views

Why are metal oxides basic and non-metals' acidic or neutral

Recently I came across the fact: Metal oxides basic and non-metals' acidic or neutral. Searching for it, partly my query is solved, as I found: Metal oxides or $\ce{O2-}$ forms $\ce{OH-}$ after ...
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5answers
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Acid Accident Treatment

What are the general ways to treat an accident involving highly concentrated or similarly dangerous acids? I have a lab instructor who recently debated with our group about treating an acid spill on ...
11
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1answer
2k views

Why can't phosphorus trifluoride be used as a Lewis acid catalyst in electrophilic substitution of benzene?

Which of the following cannot be used as Lewis acid in the electrophilic substitution of benzene? $\ce{BF3}$ $\ce{SbCl3}$ $\ce{FeCl3}$ $\ce{PF3}$ My Attempt: $\ce{BF3}$ and $\ce{...
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3answers
2k views

Why does polonium form acidic oxides?

All metals form basic oxides. Metallic oxides are basic in character. Polonium is a metal, so it should form basic oxides but it forms acidic oxides. Why are its oxides acidic in character?
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2answers
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Why does CaCO3 react with HCl, but not with H2SO4?

I have a wonderful reaction of marble chips, $\ce{CaCO3}$, with hydrochloric acid, $\ce{HCl}$, and carbon dioxide was released beautifully (fast, large volume, easy to measure and makes good visual ...
23
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4answers
58k views

Reason for the stronger acidic property of phenol than alcohol

In phenol, pulling the $\mathrm{p}_z$ electrons from the oxygen atom into the ring causes the hydrogen atom to be more partially positive than it is in aliphatic alcohols. This means it is much more ...
18
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4answers
46k views

How much can the pH change through dilution?

Consider an acidic solution with Hydrogen ion concentration, $\ce{[H+]}$ of $10^{-5}\:\mathrm{M}$. Since $\:\mathrm{pH} = -\log \ce{[H+]}$ the $\:\mathrm{pH}$ of solution is $5$. Suppose we dilute ...
17
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1answer
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Why are lactones more acidic than esters?

Lactones ($\mathrm pK_\mathrm a \sim 25$) tend to be more acidic than esters ($\mathrm pK_\mathrm a \sim 30$). I know that the lactone is fixed in a (E)-conformation, due to the ring: and that in ...
9
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1answer
3k views

How to prove that chloroform is more acidic than fluoroform? [duplicate]

How to prove that chloroform is more acidic than fluoroform? Using the concept that the inductive effect is dominant over the resonance (mesomeric effect) in the case of halide substituents: $\...
9
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1answer
985 views

Weird Wikipedia Section on Oxidizing Behavior of Nitric and Sulfuric Acids

It has been my understanding that when nitric, perchloric, or sulfuric acids act as oxidizing agents, they must exist as whole $\ce{HNO_3}$ or $\ce{HClO_4}$ or $\ce{H_2SO_4}$ molecules that are still ...
8
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2answers
8k views

Why is carbon dioxide considered a Lewis acid?

$\ce{CO2}$ is considered a Lewis acid. How it is an acid? According to Lewis: “species that accept an electron pair are acids”. But $\ce{CO2}$ can't accept electron pairs because oxygen and carbon ...
8
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1answer
20k views

Acetic acid freezing distilation

How can acetic acid be distilled by freezing when its freezing point is above the freezing point of water. Examples on the web show the water portion of the vinegar as ice and the acid as a liquid ...
7
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1answer
5k views

Can someone please explain buffers to me?

This is what I understand so far: The concept of a buffer is to minimize any swings in pH. In order to do this you need to create a solution with both acidic and basic compounds. To create one, you ...
7
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2answers
355 views

Why are lactate and lactic acid used synonymously in biochemistry?

In science there's always a misuse of the two terms. I know that lactate is the conjugate base of lactic acid. Why are they used like is the same thing? For exemple: in lactic acid bacteria (LAB) ...
6
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2answers
611 views

Does H3O+ donate a H+ to Water?

Does the hydronium ion donate a proton to water? If the collision of 2 molecules of water can cause a proton to be transferred, does hydronium 'pass' a proton to water?
5
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1answer
5k views

Are all ionic compounds salts?

According to Wikipedia: A salt is an ionic compound that can be formed by the neutralization reaction of an acid and a base. Are all ionic compounds salts? Are all salts ionic compounds?
5
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1answer
384 views

Why does the Lewis definition of acids specify a PAIR of electrons and not a single electron?

The Lewis definition of an acid is: "a compound or ionic species which can accept an electron pair from a donor compound." Why does it specify a pair of electrons and not just a single electron? I ...
4
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3answers
356 views

If change in free energy (G) is positive, how do those reactions still occur?

I was doing a couple of problems for homework: Calculate $K_\mathrm{sp}$ of $\ce{AgI}$ at $55.0\ \mathrm{^\circ C}$ Calculate $K_\mathrm{b}$ of $\ce{NH3}$ at $36.0\ \mathrm{^\circ C}$ I have to use ...
3
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3answers
6k views

dissociation of aluminum sulfate in water

I had a question as to what happens when aluminum sulfate is placed into water. After conducting research online, I got varied answers: some say that it dissociates into Al$^{3+}$ and SO$_4$$^{2-}$ ...
24
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2answers
2k views

How to properly store acids at home?

I bought different kinds of acid for experiments and home usage that I stored in secured containers into an IKEA cabinet. I just realized that despite the fact that all the containers are properly ...
19
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4answers
6k views

What's the strongest known organic acid?

What's the strongest known organic acid? Is it maybe trifluoromethanesulfonic acid or tautomer of pentacyanocyclopentadiene? EDIT: Since the question was reactivated I thought about formalising it. I ...
12
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4answers
21k views

Dissolving Organic Tissues [duplicate]

Watching some movie/TV this question came to mind, purely theoretical of course, if one wanted to dissolve a human corpse, like getting rid of a body after killing someone, is it better to use an acid ...
11
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1answer
6k views

Why is ammonia so much more basic than water?

The only reason I can think of is that the lone pairs in the oxygen in water are in lower energy orbital relative to the nitrogen in ammonia due to increased effective nuclear charge in oxygen. ...
11
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1answer
12k views

Why does HNO3 not give off H2 when reacting with Cu?

A dilute solution of which acid is most likely to produce a reduction product other than $\ce{H_{2}}$ when it reacts with a metal? (A) $\ce{HF}$ (B) $\ce{HCl}$ (C) $\ce{HNO3} $ ...
11
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1answer
582 views

What is the most acidic proton of 2-methylcyclopent-2-en-1-one?

In an acid-base reaction of $\ce{HO-}$ with 2-methylcyclopent-2-en-1-one, which is the most acidic proton? I had assumed it was one of them coming off the carbon 5 according to IUPAC numbering (&#...