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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60 views

Difficulty in understanding ionisation of sulphuric acid [closed]

$\ce{H2SO4}$ when added to water. $\ce{H2SO4 + 2 H2O -> SO4^2- + 2 H3O+}$ My sir explained me these reaction as $\ce{H}$ will give $\ce{2 H^+}$ ions to the base $\ce{H2O}$.So why does it not become ...
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1answer
3k views

What is the reaction between plain soda and sugar?

Today I was having lunch and I ordered plain soda. And some amount of sugar was added, suddenly all the liquid fell of the glass. I thought there should have been a reaction between plain soda and ...
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4answers
116k views

How do you explain pKa to non-professional?

Let's say we have substance $\ce{A}$, which is mixed with substance $\ce{B}$ to improve shelf-life because $\mathrm{p}K_\mathrm{a}$ of the substance $\ce{A}$ is $7.9$ and in mix the $\mathrm{pH}$ is $...
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1answer
75 views

Is there an “off the shelf” way to make magnesium ascorbate? [closed]

I make my own sodium ascorbate with ascorbic acid and sodium bicarb. It's easy, I get the vitamin c off ebay and the baking soda from the store. Is there a similar way to make magnesium ascorbate: ...
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1answer
50 views

Stability of pyridine derivatives

Arrange the following pyridine derivatives in the order of increasing stability of adduct formed with $\ce{BBr3}.$ Explain briefly. I'm pretty confused about which structure is the most stable. I'd ...
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1answer
94 views

pKa = pH for strong acid — strong base?

I have learnt that for a weak acid — strong base titration, $\mathrm{p}K_\mathrm{a} = \mathrm{pH}$ at the half equivalence point. However, the same conclusion is not drawn when discussing strong acid —...
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3answers
6k 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 ...
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When multiple sources give the content of an ingredient my an unqualified percentage, can I safely assume this is by weight? Or; it's not a wart

I am trying to make a simple scented shampoo and body soap for my own use and for Christmas gifts. I statr with a base of 32 oz – (a bit under a kg) of a mild commercial castille soap (Dr. Bronner’s ...
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2answers
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Why does a proton react with water to form hydronium ion and why does that ion has an overall positive charge? [closed]

Take this is an example: $$\ce{HCl(aq) -> H^+(aq) + Cl^-(aq)}$$ and $$\ce{HCl(aq) + H2O -> H3O+ + Cl^-(aq)}$$ Clearly the proton latches on to the water molecule but why? Also, why does the ...
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1answer
187 views

Understanding the increase in pH of a buffer solution upon incremental additions of NaOH analytically

So let's say we have $200\ \mathrm{mL}$ of $1\ \mathrm M$ $\ce{CH3COOH}$ solution. In this solution we have the equilibrium $\ce{CH3COOH <=> CH3COO- + H+}$. To that we add $100\ \mathrm{mL}$ of $...
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0answers
82 views

Common ion effect

Let $\ce{HA}$ ($x$ molar) be a strong electrolyte and $\ce{HB}$ ($c$ molar) — weak electrolyte. As $\ce{HA}$ is strong electrolyte, it dissociates completely: $$ \begin{array}{lcc} \ce{&HA &-&...
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2answers
46 views

Why is the gradient of the curve of a strong base titrated with strong acid small up until equivalence?

I understand the cause of the sharp decrease in pH upon reaching the equivalence point, but I don't understand why addition of relatively large amounts of the strong acid would be accompanied with ...
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2answers
90 views

Effect of dilution on weak acids pH [closed]

My textbook has a question which says what would happen to the pH of a weak acid if it is diluted with water. The answer is its pH would decrease. My teacher’s argument is that it would indeed ...
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1answer
29 views

CO2 + High humidity = transperent substance?

First I want to point out that I am not a chemist, sorry for bad description. I have CO2 incubator. CO2 concentration is 10-20% and the humidity level is around 90%. I was using a humidity sensor to ...
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2answers
286 views

What happens to concrete if you add lye to the mix?

What happens if you’re mixing concrete and you add some lye to it? Does it make it weaker, stronger or does nothing at all? I’m guessing concrete is basic so adding lye to it might expedite the ...
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2answers
2k views

Mechanism for reaction between hydrochloric acid and magnesium

Balanced equation: $$\ce{Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g)}$$ However, Cl- is a spectator ion so the actual reaction equation is: $$\ce{Mg + 2H+ -> Mg^2+ + H2}$$ Here is my proposed ...
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0answers
111 views

What are the applications of tetraxenonogold(II)?

I recently stumbled upon a pretty interesting chemical: tetraxenonogold(II) $\ce{AuXe4^2+}.$ Basically, an atom of gold with four xenons around. It is a product of a superacid reaction and it is ...
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1answer
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Why does lemon juice reduce the “fish” odor of sea food — specifically fish?

In studying about amines, I read that lemon juice is also used to wash fish because it reacts with the amines on and in the fish to convert the amines to its salt, just reducing the "fishy smell". I ...
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0answers
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Removing ashes of 3d printing resin

I'm not a chemist so excuse me if my question will bite your eye or ear. A resin 3d printing uses polymers that cure under exposure to UV light. There is a special sort of 3d printing resins made for ...
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1answer
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How do I calculate the concentration of sulphuric acid by a titration experiment with sodium hydroxide?

In my latest chem lab the objective was to create a primary standard of $\ce{NaOH}$ and use it to determine the concentration of sulfuric acid. The first part of the lab was determine the molarity of ...
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2answers
107 views

Why do we not using concentrated HCl and zinc reaction to prepare hydrogen?

First apologize for this kind silly question.One of my student ask me this question but I was unable to get a perfect answer from internet.Generally dilute HCl and impure zinc are using for hydrogen ...
3
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1answer
141 views

What is the difference between these two formulas for pH of weak acids?

In the German Wikipedia article on $\mathrm{pH}$, I found the following formula for calculating the $\mathrm{pH}$ of weak acids (which are there defined of having $4.5 < \mathrm{p}K_\mathrm{a} < ...
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1answer
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How to calculate pH of the Na2CO3 solution given ambiguous Ka values

This is the exact question I faced on an exam. Calculate the pH of $\pu{0.05 M}\ \ce{Na2CO3}\ (\ce{H2CO3}: K_\mathrm{a,1}= 4\times 10^{-7},\ K_\mathrm{a,2}= 4.7\times 10^{-11})$ Solution $$\ce{Na2CO3 -...
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3answers
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Is methanol more acidic than water?

Methanol is slightly more acidic than water. Their $\mathrm{p}K_\mathrm{a}$ values, in water, are $15.5$ and $15.7$, respectively. All other aliphatic alcohols, however, are less acidic than water. ...
2
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1answer
166 views

Finding final pH of the buffer solution without applying Henderson equation

A is beaker with $\pu{0.1 M}$ $\pu{25 cm^3}$ solution of $\ce{NH3}.$ B is beaker with $\pu{0.1 M}$ $\pu{5 cm^3}$ $\ce{HCl}.$ Now the solution of A and B is mixed. What will be the final $\mathrm{pH}$ ...
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1answer
1k views

Reaction of cinnamic acid with Br2/Na2CO3

The first reaction produces benzaldehyde, and the next one (perkin's condensation)produces Cinnamic acid.(X) Now the treatment of X with $\ce{Br2/Na2CO3}$ is whats troubling me. $\ce{Na2CO3}$ being a ...
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2answers
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Why isn't the side chain of arginine totally protonated at low pH?

I was wondering why arginine cannot be protonated at $\mathrm{pH\ 0}$ on all the $\ce{N}$ atoms in the side chain, as they all have a free electron pair. As this image shows, it can only be protonated ...
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1answer
175 views

Chloroantimonic vs fluoroantimonic acid

Does chloroantimonic acid exists? What do we get when we mix hydrochloric acid and antimony pentachloride and is the mixture stronger or weaker than fluoriantimonic acid. How about bromo and ...
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1answer
920 views

Acidic strength of organic acids. Substituted PhCOOH acids

Could someone please explain the order of acidity of ortho, para and meta substituted benzoic acids with the substituent as methyl group? Methyl group operates +I and +R effect, I believe.
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Is Hydrogen ion an acid? [duplicate]

I had an argument with a friend about this question. He says it is not an acid But I think it is as it itself can increase the pH value.
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2answers
1k views

Why ammonium hydroxide precipitates metal salts?

When I was going through the chapter on pnicotgens, I got to know that ammonia acts as a Lewis base and it dissociates in water giving out hydroxide ion and the further hydroxide of ammonia, which we ...
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1answer
61 views

Protons and osmotic potential

In a hypothetical enclosed membrane only permeable to water (including hydronium), where inside the pH is lower than the outside, would water move inside?
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1answer
2k views

Guidelines for home generation of hypochlorous acid disinfectant from salt water [closed]

I bought a home generator for making hypochlorous acid by electrolysis of a water and salt solution. I would like to figure out guidelines for safe and effective use of my generator. I have found ...
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1answer
508 views

Hydrolysis of salt

The hydrolysis of salt tells you whether a salt is acidic or basic. But it does not tell you how acidic or basic a salt is. Is there a way to determine this? My guess is that taking of the weak base ...
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1answer
2k views

How to calculate the pH of a buffered solution with Henderson Hasselbalch?

Lets say you have a buffered solution containing $0.50~\mathrm{M}$ acetic acid ($K_a = 1.8 \cdot 10^{-5}$) and $0.50~\mathrm{M}$ sodium acetate, and you want to calculate the $\mathrm{p}\ce{H}$ of ...
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3answers
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Is the Henderson–Hasselbalch equation volume independent?

Looking at this equation $\mathrm{pH} = \mathrm{p}K_\text{a} +\log\frac{[\ce{CB}]}{[\ce{A}]}$ makes me think that it is concentration independent. What I mean is, when we look at $\frac{[\ce{CB}]}{[\...
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2answers
75 views

Neutralization reactions

I saw that most neutralization reactions produce water while some do not. How can I know if water will be a product in a given neutralization reaction? I initially thought that water is a product only ...
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2answers
1k views

Acidic strength comparison between sulphuric acid and nitric acid

Why is $\ce{H_2SO_4}$ more acidic than $\ce{HNO_3}$. Shouldn't it be the other way around because $\ce{N}$ is more electronegative than $\ce{S}$? My reason: $\ce{O}$ can take electrons more easily ...
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1answer
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Is calcium chloride an acidic or basic salt?

What I reason: Calcium chloride is the salt of hydrochloric acid and calcium hydroxide. Calcium hydroxide is usually not considered a strong base, and I believe this is because of it's low solubility. ...
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1answer
47 views

Basic behavior of ammonia in aqueous medium [closed]

Thanks to the reversible reaction $$\ce{NH3 + H2O <=> NH4+ + OH-},\tag{R1}$$ we know that ammonia acts as a weak base. However, I was wondering why it ends up forming ammonium $\ce{NH4+}$ and ...
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1answer
7k views

Strength of HClO4 and resonance

Why is $\ce{HClO4}$ the strongest oxyacid? My effort: The structure of $\ce{HClO4}$ should be tetrahedral. So when there is a negative charge on oxygen, it should not be in resonance with other ...
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0answers
25 views

Can acetic or citric acid be too highly concentrated when used for cleaning copper?

I intend to clean a copper surface with acetic or alternatively citric acid. There are many different concentrations recommended by different sources on the internet. For example vinegar with 10% acid ...
3
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1answer
47 views

Difference in titration curves

In my titration curve for HCl being titrated with NaOH, the initial pH-value was plotted as 2.1 according to a pH-meter. When I found the equivalence point and calculated the concentration of HCl, it ...
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0answers
24 views

Weak acid titration curve [duplicate]

At the beginning of a weak acid titration curve (when titrated with a strong base), there is a sharp increase of pH before it levels out more due to the buffer solution that will occur. But why is ...
10
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2answers
294 views

Is d3-acetic acid more acidic than acetic acid?

The following table is from Solomons, Fryhle and Snyder Organic Chemistry, chapter 3, An Introduction to Organic Reactions and Their Mechanisms: Acids and Bases: Table 3.8 Isotopic substituents and ...
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0answers
46 views

Acidity of butyric acid vs. thiophenol

I am being asked to compare the acidities of various compounds for an assignment, but I am confused about why butyric acid is a stronger acid than thiophenol/benzenethiol. From what I was taught, I ...
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3answers
509 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) ...
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1answer
69 views

Why are alkali metal compounds like sodium hydride or sodium amide strong bases but weak nucleophiles?

I understand why compounds such as $\ce{NaH}$ or $\ce{NaNH2}$ are weak nucleophiles: as they aren't very soluble in organic solvents, they react only on the clusters' surface. But why are they strong ...
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1answer
40 views

How does the Hammett acidity function work and how to calculate it for [H2SO4] = 1,830? Any references?

I'm modelling the concentrations in the Belousov Zhabotinsky reaction. For this model, I need to convert [BrO3-] to [HBrO3]. I discovered in several papers that the following correlation applies: $$ [\...
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2answers
77 views

Can a weak acid react to give a stronger acid? [closed]

I was trying to understand why $\ce{AgCl}$ does not dissolve in $\ce{HNO3}$ and the reaction I could think of was something like this: $$\ce{AgCl + HNO3->AgNO3 + HCl}$$ I could not understand why ...

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