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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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10
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1answer
253 views

Protonating/basic site and Brønsted basicity orders of beta, gamma, and delta lactams

Consider the three cyclic amides: $\beta$-lactam $\gamma$-lactam $\delta$-lactam My question What is the basic site (site of protonation) for these three lactams? And what should be their Brønsted ...
1
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1answer
48 views

Why do strong polyprotic acids not dissociate completely, whereas strong bases with multiple (OH)- groups do?

$\ce{H2SO4}$ is a strong acid, which follows the reaction $$\ce{H2SO4 -> HSO4- + H+}$$ Not $$\ce{H2SO4 -> SO4^2- + 2 H+}$$ However, $$\ce{Ba(OH)2 -> Ba^2+ + 2OH-}$$ Is there a reason why ...
-2
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0answers
28 views

Are primary or tertiary carbanions more basic?

I am not sure about the exact IUPAC protocol for this, but I'm imagining a isobutane where the hydrogen disassociates leaving the lone pair on the tertiary carbon. I want to compare it's Bronsted ...
1
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0answers
36 views

Finding ionic radii from solubility data and density

$\pu{5.35 g}$ of a salt $\ce{ACl}$ is dissolved in $\pu{250 ml}$ of solution. The $\mathrm{pH}$ of the resultant solution was found to be $4.85.$ Find the ionic radius of $\ce{A+}$ and $\ce{Cl-}$ if ...
2
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2answers
203 views

Find the pH of an amphiprotic salt dissolved in water at room temperature

Let's say I have a polyprotic acid $\ce{H2A}$ with the following properties: $$ \begin{align} \ce{H2A &<=> HA- + H+} & K_1 &= 1\cdot 10^{-1}\\ \ce{HA- &<=> A^2-+ H+} & ...
1
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1answer
65 views

Will distillation do the job of purifying the water?

I asked about my sophisticated water purification system for a generation ship on Worldbuilding Stack Exchange, and somebody mentioned this: If you're gonna go to all the trouble of distilling it, ...
6
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2answers
4k views

Why should 2,6-Dimethyl-4-nitrophenol be more acidic than 3,5-Dimethyl-4-nitrophenol

I was trying to compare acidity of some organic compounds but can't understand some: Why should 2,6-dimethyl-4-nitrophenol be more acidic than 3,5-dimethyl-4-nitrophenol? I have been trying to ...
-2
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1answer
51 views

Can concentrated sulfuric acid oxidize iron(II) to iron(III)?

Can concentrated (18 M) $\ce{H2SO4}$ oxidize $\ce{Fe^2+}$ to $\ce{Fe^3+}?$ Or does it actually block the oxidation? I read in some forum somewhere that in order to prevent $\ce{Fe^2+}$ from being ...
4
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1answer
57 views

What is the reaction between piperine and concentrated sulfuric acid?

Piperine was chemically characterized by reaction with acids. This was done by dropping concentrated $\ce{HNO3},$ $\ce{HCl},$ and $\ce{H2SO4}$ to a sample of piperine. Both $\ce{HNO3}$ and $\ce{HCl}$ ...
2
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2answers
205 views

Help in drawing resonance structures in case of polybasic acids

While drawing resonance structure of dibasic or tribasic acid, e.g. should I take out two $\ce{H+}$ (in dibasic) or three $\ce{H+}$ (in tribasic) together or one by while drawing resonance structure? ...
2
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0answers
65 views

Acidic strength order of mineral acids in acetic acid

Explain this acidic strength order $\ce{H2SO4} > \ce{HCl} > \ce{HNO3}$ in acetic acid. My Attempt Stability of conjugate base is proportional to the acidic strength of acids in acetic acid. $\...
0
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1answer
36 views

Vinegar salt reaction to produce acid; does it matter what type of vinegar I use

I am trying to get get hydrogen chloride gas by using the reaction sodium chloride + vinegar = HCl(g) + sodium acetate, does it matter what type of vinegar I use eg apple cider vinegar, malt vinegar; ...
4
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0answers
31 views

acid strength: Periodic trends vs delocalisation, which one is more important

In 1st year chemistry questions, the concept of acid strength is often introduced to students including the 3 factors that provide a heuristic explanation for most of the common acids and conjugate ...
2
votes
1answer
45 views

How to determine if a compound is a strong, weak, or non-electrolyte? [closed]

I'm stuck on questions asking whether a given chemical formula is a strong or weak electrolyte in an aqueous solution. I did some research online, but could not get a specific solution that I could ...
0
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0answers
30 views

Hydrogen bonding in o-nitrophenol versus o-nitobenzoic acid

p-nitrophenol is more acidic than o-nitrophenol because of hydrogen bonding in the latter. If I apply the same logic, then o-nitrobenzoic acid should be less acidic than p-nitrobenzoic acid. However, ...
0
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0answers
68 views

Can I reverse an iron redox reaction with potassium hydroxide and electricity?

For a school project, about clean energy, me and my team are trying to build an iron battery. We are using a piece of iron (anode), potassium hydroxide (electrolyte), carbon electrode (cathode) ...
1
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0answers
33 views

The most acidic hydrogen of 4‐hydroxybutanenitrile

Identify the most acidic hydrogen atom in the compound below: $$\ce{NC-CH2-CH2-CH2-OH}$$ My teacher said that the $\ce{H}$ connected to $\ce{O}$ is the most acidic since $\ce{O}$ is more ...
3
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2answers
6k views

Long-term storage of Ascorbic Acid mixed with Sodium Bicarbonate

Every day I mix two parts of ascorbic acid powder with 1 part of sodium bicarbonate powder and place the resulting powder into an airtight container. I have noticed that if the resulting powder is ...
-1
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2answers
107 views

Why doesn't ethanol dissolve in sodium bicarbonate?

Today I experimented with different solvents and solutes and was a bit surprised by one result. When I added ethanol to dilute sodium bicarbonate and tapped the test tube against my palm to mix it, I ...
7
votes
3answers
21k views

How to determine the pH of a mixture of two weak acids?

We’ve two solutions: Solution 1 $\ce{HCOOH}$ its concentration is $c_1=10^{-2}\ \mathrm{mol/l}$ and its volume is $V_1 = 50\ \mathrm{ml}$ and its $\mathrm{pH}_1 = 2.9$. Solution 2 $\ce{CH_3COOH}$ ...
1
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2answers
858 views

Applying Henderson–Hasselbalch equation to amino acids: which pKa to use to calculate Z-/HZ ratio?

I was wondering which $\mathrm{p}K_\mathrm{a}$ to use when calculating the ratio of $\ce{HZ}$ to $\ce{Z-}$ of amino acids, the Henderson–Hasselbalch formula used: $$\mathrm{pH} = \mathrm{p}K_\text{a} ...
7
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3answers
15k views

Is ammonium a strong or weak conjugate acid?

Ammonium, $\ce{NH_4^+}$, is the conjugate acid of ammonia, $\ce{NH_3}$. I have searched the Internet and so many different answers pop up. The rule of thumb that I read was that a strong acid has a ...
-1
votes
1answer
23 views

Using a weak acid to prevent the precipitation of Mg(OH)2

I have this exercise in my chemistry book, and I have been staring at it for so long but unfortunately I have no single idea what to do and where to start. I will be so thankful for any help. $0.05$ ...
5
votes
3answers
63k views

What is the maximum molarity of aqueous HCl?

Here is a problem a made up: We have some aqueous $\ce{HCl}$. What is the maximum possible molarity of the $\ce{HCl}$? How do I solve this? I don't have any good ideas.
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0answers
32 views

Why is BF3 hard while BBr3 is borderline(HSAB concept)?

This is a table given in a text book regarding hard acids How come BF3 is a harder acid than BBr3? My reasoning: To check which is harder: 1.Both difficult to polarize 2.Both similar in size It ...
6
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1answer
4k views

Buffer formation in weak acid/strong base titration?

I'm a little confused about what happens when you titrate a weak acid or base. For example, let's say that you are trying to titrate a weak acid. Based on this question, it seems like the weak acid ...
2
votes
1answer
592 views

Arrange the following in increasing order of acidity: water, ammonia, ethyne and ethane

I know that ethyne is more acidic than ethane because of more s character. For water and ammonia, I used the fact that oxygen is more electronegative than nitrogen and will be able to stabilize the ...
0
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1answer
68 views

Neutralization between Ca(OH)2 + H2SO4 in a 30% hydrogen peroxide solution

I have performed an experiment where I added an excess of $\ce{Ca(OH)2}$ base to a solution consisting of 5 mL of 30 % hydrogen peroxide (buffered at pH 5) and a very small amount of sulfuric acid (...
5
votes
4answers
30k views

Sulfuric acid fumes from cleaning shower drain

This morning a workman came by to my newly rented property to fix a few things, among which a slightly blocked bathtub drain. He let some mild water run continuously and he poured down a chemical, ...
1
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0answers
77 views

Primitive Technology - Production of NaOH

We need to produce NaOH with primitive Technology. This is Part 1 of my Gilligan's Island Challenge series (Part 2). You are stuck on an island with access to a beach, a forest, a river, a lake, and a ...
0
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1answer
169 views

How do I calculate the ensemble-average net charge of an amino acid at given pH?

I am given an amino acid with an ionizable side chain at a certain pH. How do I determine the net charge of that amino acid when there are mixed protonation states of one or more of the groups at that ...
0
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1answer
82 views

Acetone basicity [closed]

Why doesn't acetone have high basicity? The C−O bond is polar, O becomes partially negatively charged and it should attract protons, becoming a strong base.
0
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0answers
27 views

What will be the Lewis acid and Lewis base in the reactions between aluminium(III) aqua complex and hydroxide?

$\ce{Al^3+}$ in water will be hydrated, formed a complex ion $\ce{[Al(H2O)6]^3+(aq)}$ that can neutralize hydroxide ion according to the following reactions: $$ \begin{align} \ce{[Al(H2O)6]^3+ + ...
3
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6answers
11k views

Decreasing order of basic strength

I need to find the decreasing basicity of the following compounds(I, II, III, IV, respectively): I know that to compare the basic strengths, we need to find the stability of their conjugate acids. ...
-1
votes
1answer
22 views

Can I use Ascorbic acid powder as a preservative to extend the shelf life in pickled brine recipe? [closed]

Can I use Ascorbic acid powder as a preservative to extend the shelf life in pickled brine recipe made with vinegar?
3
votes
0answers
986 views

Acidity comparison of charged group 16 hydrides

March's Organic Chemistry (7th ed - page 337 under "Periodic Table Correlations" in chapter "Acids and Bases") states that: $\ce{H3O+ > H3S+ > H3Se+}$ is the acidity order of these charged ...
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2answers
123 views

Why exactly is a fluoride anion a stronger base than iodine anion? [closed]

First off, I've learnt that stronger acids produce weaker conjugate bases (through Brønsted–Lowry acid–base theory). Then I looked at the $\mathrm{p}K_\mathrm{a}$ values of $\ce{HF}$, $\ce{HCl}$, $\...
2
votes
2answers
12k views

Electrolysis of diluted sulfuric acid

My teacher told me that electrolysis of dil. $\ce{H2SO4}$ (concentration below $50\%$) using inert electrodes results in gradual increase of the concentration of $\ce{H2SO4}$. I can't seem to figure ...
1
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1answer
154 views

Why is maximum buffer capacity for some diprotic buffers not when pH = pKa?

According to Rajkovic et al. [1]: $$β = \frac{[\ce{H+}]}{K_\mathrm{w}} + 2.303\cdot\frac{[\ce{H+}]\cdot K_\mathrm{a}\cdot c}{[\ce{H+}] + K_\mathrm{a}}$$ where $K_\mathrm{a}$ is the ...
0
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1answer
97 views

Steric Inhibition of Resonance in ortho-substituted Benzoic Acids

It is given that due to Steric Inhibition of Resonance (SIR), the acidity of ortho-substituted benzoic acid increases with respect to benzoic acid. If this is the case then the conjugate base of the ...
3
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2answers
30 views

Can mechanical agitation increase the reaction rate?

The specific example I saw recently was cleansing of concrete (portland cement) film from brick using a diluted muriatic acid. It appeared that the more scrubbing was used, the quicker the cleaning ...
0
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0answers
32 views

Will Chlorodifluoromethane (R22 refrigerant) react with calcium metal?

I am attempting to recycle or find a use for chlorodifluoromethane, however I do not want to risk venting it into the atmosphere or exposing myself to hydrofluoric acid. Ideally, I would like to ...
13
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4answers
17k 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, ...
12
votes
1answer
10k views

Relative acidities of alkanes, alkenes, and alkynes

How does one explain the trend in bond lengths and acidity of the following hydrocarbons? $$\begin{array}{ccc} \hline \text{Species} & \ce{C-H}\text{ bond length / Å} & \mathrm{p}K_\mathrm{a} ...
3
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1answer
77 views

Thermodynamic vs kinetic basicity [closed]

I'm writing something related to basicity and came across few papers that distinguish thermodynamic and kinetic basicity. "In particular, the study of hydrogen bonding (H-bonding) within proton ...
2
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1answer
879 views

Why is magnesium sulfate acidic? Why are my calculations showing that it is basic?

Let's say I was dissolving $\pu{1M}~\ce{MgSO_4}$ into water and I wanted to find the pH. I would go right to the reaction of the dissociation of $\ce{Mg(OH)_2}$: $$\ce{Mg(OH)_2 <=> Mg^2+ + 2OH-}...
-1
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1answer
60 views

Calcium carbonate and hydrochloric acid - data analysis [closed]

I conducted an experiment in which $\pu{10mL}$ of dilute hydrochloric acid was added to a beaker, and this acid was heated up to room temperature ($\pu{22 ^\circ C}$) using a Bunsen burner. Then, $\pu{...
4
votes
3answers
190 views

Why isn't my galvanic cell making enough voltage?

I'm in kind of a pickle here. I made a galvanic cell of Lead and aluminium for a chemistry internal assessment but unfortunately, it didn't turn out so well and neither me nor my teacher has any clue ...
26
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1answer
4k views

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 ...
2
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1answer
2k views

Comparing Basic strengths of different species

I was doing questions on organic chemistry. I came across tonnes of questions where I was required to compare basic and acidic strengths. Comparing acidic strengths is fine — I remove an $\ce{...