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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6
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2answers
10k views

Alkalis and Bases

I just learnt about acids and bases at class.I noticed that my textbook mentions the term "alkali/alkaline" and sometimes it mentions "base/basic". As far as I know, alkalis and bases are metal oxides ...
5
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3answers
136 views

Changes in pH when adding substances other than acids or bases

If I start out with 100 mM acetic acid, what substance (to a final concentration of 1 M) could I add to change the pH considerably? I was thinking of NaCl or ethanol or acetone. Substances added ...
2
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1answer
17 views

When will acid-base reactions occur before substitution reaction

For example, given the reaction below: The substrate is secondary, the solvent is aprotic and it is to react with a strong bulky base. From this, I assumed that the reaction would be $\ce{E2}$. ...
0
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0answers
41 views

Can a cation form a bond with only the oxygen in hydroxide ion?

$$\ce{Al2O3 + 2 NaOH → 2 NaAlO2 + H2O}$$ In this reaction between an amphoteric oxide and a base, I do not understand how $\ce{Al}$ makes a bond with oxygen atoms since the water is found in the ...
0
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0answers
25 views

Create a buffer using CH3COOH and NaCH3COO that has a pH of exactly 3.75.? [closed]

a 50 mL sample of your buffered solution will have to be able to withstand the addition of 25.0 mL of 0.100 M NaOH solution. the buffered solution will break after the addition of no more than 35.0 ...
1
vote
1answer
52 views

Calculate the pH of buffer solution

PROBLEM: A solution was prepared by mixing $\pu{25.00 mL}$ of $\ce{NaOH}$ $\pu{(c = 1mol/L)}$ and $\pu{10.00 mL}$ of acetic acid $\pu{(c = 2.5 mol/L)}$ in water to give $\pu{250 mL}$ of solution. ...
0
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2answers
221 views

Which of the following is the most basic compound?

Which of the following is the most basic compound? $\ce{HS-}$ $\ce{H3Si-}$ $\ce{H2P-}$ $\ce{Br-}$ I can't figure out which of these is the strongest base. Would it be $\ce{H3Si-}$, ...
3
votes
1answer
37 views

Acid-Base Reaction in MacGyver Episode “Countdown”

This question is about the old MacGyver show, Season 1, Episode 14, "Countdown." Could someone please explain how/why MacGyver neutralizes the acid in the bomb? He claims it is an electrolyte switch, ...
17
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3answers
844 views

Is the proton the strongest acid?

Having looked at the various definitions of acids and bases and having refined my understanding of it after learning about the inadequacies of pKa and the novel use of the Hammett acidity function, I ...
2
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0answers
729 views

Decarboxylation mechanism and stability of α,β-unsaturated and α-hydroxy acids

I was wondering why α,β-unsaturated and α-hydroxy acids undergo decarboxylation. Also, I'm aware of neither the products nor mechanism. All I know is that β-keto acids and α-nitro compounds have ...
0
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1answer
44 views

Reaction between an acid and acid

My initial thought was that the stronger acid will act as an acid and the weaker acid as base like the reaction between $\ce{H2SO4}$ and $\ce{HNO3}$ but in this reaction there is a lone pair available ...
4
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3answers
353 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 ...
0
votes
2answers
48 views

How can you deduce from the structure that probenecid is an acid and ephedrine is a base?

Probenecid contains a carboxyl group, indicating an acid. But it also contains a nitrogen atom, which indicates a base? How can I decide that it is an acid and not a base? I have the same problem ...
2
votes
1answer
1k views

Why is a weak base more able to deprotonate a strong acid than a weak acid?

Very basic question, but I'm rather confused. Say I want to separate a carboxylic acid $(\ce{RCOOH},$ $\mathrm{p}K_\mathrm{a}~5)$ from a phenol $(\ce{ArOH},$ $\mathrm{p}K_\mathrm{a}~10)$ via acid-...
4
votes
2answers
392 views

Why are tertiary amines less basic than secondary and primary amines in water than when vapourised?

In gaseous state: $$\ce{(CH3)3N} > \ce{(CH3)2NH} > \ce{CH3NH2} > \ce{NH3}$$ However, when dissolved in water: $$\ce{(CH3)2NH} > \ce{CH3NH2} > \ce{(CH3)3N} > \ce{NH3}$$ My notes ...
7
votes
1answer
24k views

How does sodium bicarbonate act as a deodorizing agent?

I was reading this other question on the site: Deodorizing using baking powder instead of baking soda. Apparently, baking soda is used quite often as a cleaning and deodorizing agent. From what I ...
0
votes
1answer
480 views

Reaction of nitro compounds with strong alkali?

Why does a primary and a secondary nitro compound behave as an acid in the presence of strong alkali whereas tertiary nitro compounds do not? Can anyone explain it with reactions?
1
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1answer
94 views

Pale blue species forming during electrolysis of NaHCO3

I have a solution of 3500 ml $\ce{H2O}$ + 454 g $\ce{NaHCO3}$ in electrolysis at a potential of 12.5V using a lead anode and copper cathode. The surface areas aren't measured but they are enormous. I ...
2
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0answers
53 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 &-&...
53
votes
4answers
182k 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 ...
2
votes
1answer
43 views

Neutralisation Reaction Confusion

What will happen when $\pu{1 mol}$ of $\ce{H2SO4}$ reacts with $\pu{1 mol}$ of $\ce{NaOH}$? Will $\pu{1 mol}$ each of $\ce{NaHSO4}$ and water be formed? Or will $\pu{0.5 mol}$ of $\ce{H2SO4}$ will ...
2
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0answers
52 views

Amount of benzoic acid required to alter pH of a NaOH-solution

I am trying to do a practice problem but I can't figure it out: How many grams of benzoic acid needs to be added to 0.10 l of a NaOH-solution with a concentration of 1.0 mM to reduce the pH of said ...
-1
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1answer
45 views

Identifying weaker base

Can you tell me the reason behind the answer to this: Which is the weaker base? (a) o-cresol; (b) Trifluoro-o-cresol. Answer: (b) trifluoro-o-cresol. I'm not a student in any institution. So ...
3
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2answers
412 views

A basic question about tetramethylammonium hydroxide --strong or weak?

This is a follow-up to the question here. There is an answer claiming that tetramethylammonium hydroxide (TMAH) is a suitable strong base that can be used instead of the usual alkalies to reach pH 14....
-3
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2answers
132 views

pH of strong acid weak acid mixture [closed]

Question: $\ce{H2S}$ ($\pu{0.1M}$; $K_\mathrm{a} = 1.2×10^{-20} $) and $\ce{HCl}$ ($\pu{0.3M}$) with same volume are mixed together. What is the resultant $\mathrm{pH}$? My approach: Let the volume ...
1
vote
1answer
72 views

What are the enthalpy and entropy contributions to carboxylic acids dissociating in water?

Carboxylic acids such as acetic acid do not dissociate much in the gas phase. In aqueous solution, however, they act as acids (proton donors). $$\ce{CH3COOH(aq) <=> H+(aq) + CH3COO-(aq)}$$ ...
4
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0answers
73 views

Solubility of PbSO4

The solubility of $\ce{PbSO4(s)}$ increase with the addition of $\ce{H2SO4}.$ Why? I don't quite understand this. When dissolving $\ce{PbSO4(s)}$ we get the equilibrium equation: $$\ce{PbSO4(s) <=...
-1
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1answer
164 views

Methyl Orange Indicator-Reason for small amount of NaOH [closed]

I used methyl orange as my indicator to titrate a weak acid: At first, I added 3 drops of methyl orange to a solution of the weak acid, $\ce{CH3COOH}$, and the solution turned red. Then, after ...
2
votes
1answer
43 views

Calculating molecular weight of an acid based on given values of mass, volume, pH and pKa

This is what I thought was an easy problem but according to a given answer I am doing it wrong: $\pu{11 mg}$ of a monoprotic acid was dissolved in $\pu{0.5 l}$ of water. The resulting $\mathrm{pH}$ ...
1
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0answers
38 views

What acids will Sodium Lauroyl Methyl Isethionate yield after hydrolysis? [closed]

As far as I understand, after hydrolysis Sodium Lauroyl Methyl Isethionate will yield sodium, lauroyl and methyl alcohols, and isethionic acid. Meaning lauroyl is referring to the fatty acid alcohol ...
0
votes
1answer
77 views

Basic strength of nitrogen

What is the order of basic strength of nitrogens in the compound given in the figure? $$\ce{ H2\overset{.\!\!.}{\underset{(γ)}{N}}-\overset{.\!\!.}{\underset{(β)}{N}}H-\overset{\overset{\huge O}{||}}{...
0
votes
0answers
75 views

Trichloroacetic acid aqueous solution

I have bought some anhydride of trichloroacetic acid (TCA) and would like to prepare an acidic solution. My problem is, that I don't know how much "powder" to mix with how much water to produce an x% ...
1
vote
0answers
29 views

Electron-donating trends for ligands bound to metal complexes

Imagine an inorganic complex with a bunch of terminal ligands. All else the same, would $\ce{F-}$ or $\ce{Br-}$ ligands be more electron-donating and why? Of course, in terms of $\mathrm{p}K_{\mathrm{...
3
votes
1answer
216 views

What happens with enol and ketone

What process happens between an enol and a ketone, so that the ketone will enolate and become acidic? Please, explain what happens with them in this process?
0
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1answer
2k views

How does diluting an acid change pH?

By the Henderson–Hasselbalch equation, log (salt)/(acid) term is a ratio of the concentrations. So, how can dilution change the pH of the acid as the concentrations of both salt and acid would change ...
7
votes
1answer
633 views

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. ...
3
votes
1answer
436 views

When to use 1/Ka vs Kb [closed]

I'm really unsure what the difference is. We're using these when calculating $K$ of combined reactions. In general, I am also confused what $K$ is in comparison to $K_\mathrm{a}$ and $K_\mathrm{b}$. ...
0
votes
3answers
74 views

Are there any guidelines for what constitutes an “organic acid” regarding storage requirements?

I am moving a large amount of chemicals to a new lab and I’m curious about any guidelines for chemical separation. I’ve seen suggestions that organic acids and non-organic acid be stored separate from ...
16
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3answers
3k views

Does nitrogen inversion affect the basicity of amines?

If I were to compare the basic strength of 1-azabicyclo[2.2.1]heptane and triethylamine: Can I say that 1-azabicyclo[2.2.1]heptane is more basic than triethylamine because the lone pair of electrons ...
2
votes
1answer
2k views

Is heating dilute HCl dangerous?

Say dilute $\ce{HCl}$ is used to convert some alkaloid to salt form, then the alkaloid is dried with heat, would gaseous $\ce{HCl}$ be released in the process? Is there a threshold concentration of ...
28
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5answers
54k views

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 ...
9
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4answers
3k views

Strong and Weak Acids/Bases

I'm so confused... $\ce{HClO}$ is a weak acid. then why is its conjugate base, $\ce{ClO-}$, a weak base in water? shouldn't they be inversely proportional? shouldn't $\ce{ClO-}$, be a strong base? ...
0
votes
0answers
86 views

Sodium bicarbonate, varying acetic acid, measuring carbon dioxide volume, understanding results

With my 6yo daughter, I have conducted a simple experiment. We used 1/4 tsp (we don't have sub-gram scales) of bicarbonate of soda for each test. In each test, we used a different amount of vinegar (5%...
1
vote
1answer
126 views

What will be the order of acidity in the following compounds? [closed]

What will be the order of acidity in the following compounds ? From My point of view it should be 3>1>2>4. But the answer given is 3>2>1>4. Can anyone explain how ?
0
votes
0answers
25 views

H-bonding in o-hydroxybenzoic acid [duplicate]

Amongst all hydroxybenzoic acids the ortho isomer is most acidic and the major reason is intramolecular H-bonding in the anion. My question is that isn't the loss of proton destabilising the molecule ...
1
vote
1answer
30 views

pKa and equivalence point [closed]

I was doing a titration and using $\ce{NaOH}$ as the titrant. The analyte was a weak acid with a $\mathrm{p}K_\mathrm{a}$ of 4.90. Today I want to use another acid with a $\mathrm{p}K_\mathrm{a}$ of 4....
0
votes
0answers
49 views

Calculating pH of solution

What is the $\mathrm{pH}$ when you dissolve equal amounts of $\ce{NaHCO3}$ and $\ce{Na2CO3}$ in water? When both of the compounds are dissolved, we will have equal amounts of $\ce{HCO3-}$ and $\ce{...
4
votes
0answers
45 views

Basicity af N containing aromatic species

Hello friends, I got struck in this interesting question on basicity. I am able to get different answers applying different methods. In general, for these compounds we have to see the lone pair ...
5
votes
0answers
43 views

Why does my rainwater turn yellow if I increase the pH to 7?

My rainwater is colourless when collected, but if I add a small amount of sodium hydroxide to increase the pH to about 7, after a few days it goes yellow. The colour change happens more quickly if I ...
-6
votes
1answer
69 views

Reaction of HF in water [closed]

I was wondering, if we put $\ce{HF}$ into a glass of water the acid will be dissolved according to this reaction: $$\ce{HF->F- + H+}$$ Now there is a proton travelling across the water. All $\ce{...