Tagged Questions

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 is on the other hand a chemical species/ molecular entity having an available ...

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Buffer Power of the amphiprotic substance

The mass balance for a generic amphiprotic substance $[AH^-]$ this: $$ [HA^-]=C \cdot \dfrac{K_{a1} [H_3O^+]}{K_{a1}\cdot [H_3O^+] + [H_3O^+]^2 + K_{a1} \cdot K_{a2}} \quad Eq.1 $$ where: C = ...
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0answers
19 views

Imine stability in acids and bases

I understand that imines can be hydrolyzed in acidic medium. But what about in basic medium? Can imines still be hydrolyzed? I have a plausible mechanism ... nitrogen's withdrawal of electron ...
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0answers
18 views

Determination of acid contents in sour fruits project? [on hold]

Determination of acid contents in sour fruits project? Any idea about it or any references.
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1answer
48 views

In which direction does imidazole affect the pH?

I'm reading something about nickel affinity chromatography and it talks about using imidazole to affect pH. In which direction does it change the pH?
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0answers
26 views

Positive and negative charges and acidic or basic media

I am told that we shouldn't have any negative charges when showing a mechanism of something that occurs in basic media. The opposite goes for a mechanism occurring in acidic media. Are there any ...
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1answer
26 views

Is atom-clean aluminum active enough to react with alkali salts?

Thermally evaportated $\ce{Al}$ under high vacuum is free of oxidized species and highly active. But is it active enough to even substitute the alkali cationic metal in alkali salts, like $\ce{LiOH, ...
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1answer
34 views

Buffer solution calculation

Consider a buffer solution made from mixing 1 ml of $\ce{Na2HPO4}$ (0.1 M) and 9 ml of $\ce{NaH2PO4}$ (0.1 M) having $pKa$ of 7.21. When 1 ml of $\ce{HCl}$ (0.1 M) is added the measured $pH$ ...
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2answers
40 views

find the pH where is maximum the concentration of a amphiprotic substance

Considering a general amphiprotic substance NaHA. I know that the maximum concentration of the specie $HA^-$ is found at $pH = \dfrac{pKa1+pKa2}{2}$. Why? How i can confirm this statment? The ...
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2answers
50 views

Write a Net Ionic Equation to Represent the Reaction of Aqueous Ammonia with Propionic acid

I would like to know how do I begin to solve a problem like this? That is finding the formula equation? I would assume that it would be $$ \ce{NH3 + CH3CH2COOH -> NH3 + CH3CH2COOH + H2O} $$ I ...
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1answer
12 views

When mixing lye and citric acid, which citrate will form?

I'm trying to combine precise amounts of citric acid and lye to get sodium citrate with minimal amount of reacted acid/base. I'm not so sure how stochiometry works, but I could sure learn that from ...
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2answers
1k views

If caffeine is an alkaloid, why is coffee acidic?

I have just put together on my mind these two facts: caffeine is an alkaloid and brewed coffee is slightly acidic (pH = 5). My Biology teacher and my Chemistry teacher could not elaborate satisfying ...
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0answers
27 views

How do I determine the Ka using an ICE chart of an unknown acid titration using NaOH

two trials were ran using 10 mL of an unknown acid into a NaOH solution until the pH reached equivalence (pH of around or as close to 7). Using this data, I have made two graphs and I am supposed to ...
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2answers
47 views

Why do acids ionize in solution if they are covalently bonded?

Maybe I am wrong, but I thought acids were covalently bonded since hydrogen doesn't form ionic compounds. For example, wouldn't $\ce{HCl}$ look like: Since the electrons are shared, why does it ...
6
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3answers
343 views

Why are weak acids weak?

What are weak acids? My chemistry and biology class's skimmed over them briefly but nothing in depth. I understand that an acid is weak if it partially dissociates and breaks down into ionic ...
0
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3answers
72 views

How do you explain pKa to non professional?

Let's say we have substance A which was mixed with substance B to improve shelf-life because pKa of the substance A is 7.9 and in mix the pH is 5.2. Does this mean that in the solution with pH near 8 ...
3
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1answer
43 views

Find the initial volume of the weak acid given a titration graph

Question Below is a picture of a titration between a weak acid, $\ce{HA}$, and a 0.150 M $\ce{NaOH}$ solution. Find the initial volume of the weak acid in millilitres in this titration. My work ...
3
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2answers
72 views

What makes protons give the property of acidity?

Bronsted Lowry definition of an acid says that an acid gives away protons. What I don't understand is what makes dissolved protons grant the property of acidity? Like, why would dissolved protons eat ...
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3answers
3k views

Which is the strongest acid?

According to Wikipedia $\ce{HeH+}$ and Fluoroantimonic Acid are the strongest. According to Nature, Carborane acid is the strongest, but Wikipedia says fluoroantimonic acid is stronger... Links: ...
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1answer
166 views

Which is more basic, hydrazine or ammonia?

Which of the following will be more basic, hydrazine $\ce{H2N-NH2}$ or ammonia $\ce{NH3}$? My chemistry teacher said that $\ce{NH3}$ is more basic since after giving $\ce{H+}$ to hydrazine results in ...
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1answer
15 views

Ionic Equilibrium

Calculate the pH of a solution which contains 100mL of 0.1M HCl and 9.9mL of 1.0M NaOH. While calculating the concentration of H+ ions, why shouldn't we consider the H+ ion concentration from water?
2
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1answer
52 views

Alkyne formation from vicinal dihalide

Why must 3 equivalents of sodium amide be used here to form the alkyne? The part I specifically have issue with is in red. From what I understand, we should just use 2 equivalents of sodium amide to ...
4
votes
1answer
88 views

Which proton is more acidic in this compound?

I'm having trouble determining which of these protons is more acidic. I was thinking the solution had something to do with the double bond in the aromatic ring, but I'm still not sure. If anyone can ...
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0answers
23 views

Degree of dissociation of strong electrolytes in concentrated solutions of ionic substances

Why is the dissociation of strong electrolytes complete in very dilute solutions of ionic substances but less likely to be so in more concentrated solutions? Before seeing this, I thought a strong ...
3
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2answers
69 views

Interesting ionization of sulfuric acid

I just need an explanation of why it is a strong acid in its first ionization and a weak acid its second ionization. It becomes $\ce{HSO_4-}$. From what I have learned about oxoacids, the bond ...
5
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2answers
126 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: ...
2
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1answer
39 views

Finding rate of acid - base reaction

Given the reaction between $\ce{CH_{3}COOH_{(l)}}$ and $\ce{NaHCO_{3_{(s)}}}$ which happens in same pressure but in different temperatures, is there any way to mathematically compare between the rate ...
2
votes
1answer
75 views

Material that doesn't melt at 800 deg F, but can be dissolved?

I'm a sculptor and I have a chemistry/plastic question. I thought here would be a good place to ask. I'm looking for a substance (probably a plastic) that has these characteristics: Doesn't melt at ...
0
votes
1answer
35 views

Acid-Base Neutralization [duplicate]

What is the net ionic equation for the reaction between phosphoric acid and sodium hydroxide? is it 1)H+ + H2PO4- + OH- -----> PO4-3 + H2O or 2) H+ + OH- -----> H2O
8
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1answer
554 views

Why is proton transfer so fast?

Why is proton transfer always kinetically favored? In other words, why are Bronsted acid-base reactions so quick? Is it because protons are generally unhindered, sterically? This seems plausible; ...
1
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0answers
34 views

pH of calcium carbonate in ammonium chloride solution (theoretical; not a calculation question)

Consider calcium carbonate saturated in 1.0 M ammonium chloride solution. I have calculated the pH of this solution analytically (with mass and charge balance) to be 6.92. Now, how would the actual ...
3
votes
1answer
60 views

pH of a buffer solution calculation

Calculate the pH of a mixture of $75\text{cm}^3$ of methanoic acid solution of concentration $0.10\text{mol dm}^{-3}$ and $75\text{cm}^3$ of sodium hydroxide solution of concentration $0.050\text {mol ...
1
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1answer
69 views

Conductance and Conductivity of acid base titration?

I have a question with NaOH initially present with given concentration and conductivity, then an equal volume of given concentration of HCl is added and the final conductivity is given, again a same ...
3
votes
1answer
84 views

Why can't this be used as a buffer solution?

Explain, using a chemical equation to aid your answer, why a mixture of $50~\mathrm{cm^3}$ of $0.10~\mathrm{\frac{mol}{dm^3}}$ ammonia solution and $50~\mathrm{cm^3}$ of ...
2
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1answer
23 views

Corrosiveness of Acid

Is the corrosive nature of acid relative to some substance quantifiable like acid dissociation constant (Ka)? If yes, what can be used to describe the corrosive nature of an acid? For example, it is ...
0
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1answer
64 views

How could the pH of this solution rise instead of fall when exposed to the atmosphere?

I have a couple of big barrels with a 50L demi-water solution of the following nutrients: $$ \begin{array}{rl} 200~\mathrm{\mu M} & \ce{NH4NO3} & +\\ 30~\mathrm{\mu M} & \ce{KCl} & ...
6
votes
3answers
72 views

Could neutralisation of safe chemicals produce dangerous ones?

I'm basically thinking whether I could potentionally poison myself while neutralising strong acid/base by some weak base/acid when I accidentally spill it, touch it or when I'm cleaning reaction ...
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1answer
48 views

Grocery store crystalline citric acid

Which type of citric acid crystalline powder do they sell in grocery stores? Is the concentration of citric acid in the crystals 100%?Is it anhydrous or a monohydrate?
1
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1answer
36 views

carbonic acid reaction

is it possible that if we blow water (hot/cold) can cause a bond between CO2 from expiration and H2O of the water, and say, maybe become H2CO3? Is H2CO3 a dangerous component? Thx, iccang-Indonesia
2
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1answer
49 views

Acidity of ester and benzoic acid

Can the oxygen in an ester participate in resonance donation? I think so, although the donation is slight. The hybridization is correct. However, resonance withdrawal by the ring via the oxygen ...
2
votes
3answers
73 views

Acidities of amines and carboxylic acids

I have been told that the first of the two acids is the stronger acid. According to this person,deprotonation for both occur at the nitrogen.The resulting conjugate bases include,respectively a ...
0
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1answer
29 views

Basicities of meta-nitrophenoxide and para-nitrophenoxide

The negative oxygen is the site of protonation. Size and EN are the same for both oxygens. We are mainly looking at resonance (and possibly inductive) effects here. We want the least resonance ...
1
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2answers
74 views

How does alkaline hydrolysis of peptides occur?

I have been learning about zwitterions and the isoelectric point, and have been trying to apply this to hydrolysis of peptides. From the diagram in my textbook, I can see that when acid hydrolysis ...
1
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1answer
43 views

What happens to the amino acid when it is in a solution with the pH of its isoelectric point? (zwitterions)

I am learning about zwitterions and am confused about the following: From what I understand, when amino acids are in their solid form, they exist as zwitterions which is why they have such a high ...
0
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1answer
97 views

Removing HCl from water

I have water contaminated with dissolved chlorine: $\ce{H2O + Cl2 <=>HCl + HOCl}$ During electrolysis, this is an issue. These are my products: $\ce{NaCl + H2O ->T[electrolysis] NaOH + Cl2 ...
5
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1answer
45 views

What happens when 0.02 mole NaOH is added to a buffer solution?

I am asking this question for my son. (This question is related but we still have our confusions.) We have one liter buffer solution of 4.74 pH which contains 0.1 mole $\ce{CH_3COOH}$ and 0.1 mole ...
4
votes
1answer
183 views

Is the Ocean acidification inconsistent with the Bjerrum plot?

$\ce{CO2}$ dissolves in water and goes through chemical reactions and exists at different concentrations of, dissolved $\ce{CO2}$, carbonic acid, bicarbonate, and carbonate. The Bjerrum plot ...
4
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1answer
124 views

Adjusting PBS with HCl: pH drift after dilution of phosphate buffer

It is some kind of everyday lab science and with a feel of shame I cannot answer this observation. I noticed a pH drift (~0.5 units) of my 10X phosphate buffer (PBS), when I adjust the pH with ...
1
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0answers
13 views

Enzyme Assay - pectinase

I am working on Enzyme Assay.I assayed the enzyme in different buffers from $pH\ 1-12.5$ However,the enzyme has good activities starting from $pH\ 1-10.5$ Is that possible to have enzyme activity in ...
1
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1answer
60 views

Why can't organic acids be concentrated and used like concentrated sulphuric acid, etc?

Is it possible to make organic acids concentrated like inorganic acids like concentrated sulphuric acid, etc?
3
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0answers
15 views

Dissolving Time Function for Concrete

So I was just exploring some ideas on my own and am having trouble analytically solving the following: Let $D(n,m,T)$ be the time it takes to dissolve an n x n x n cube of concrete in m molar HcL at ...