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).
3,189
questions
0
votes
2
answers
3k
views
Are burns from Lye or Potash that bad?
I read that the chemicals potassium hydroxide and sodium hydroxide are extremely corrosive and will cause severe burns but I also see videos of people saying that if you get lye on you, then just wash ...
- 1
0
votes
2
answers
7k
views
What are acid/base sensitive groups?
My textbook says that Clemmensen Reduction cannot take place in the presence of an acid-sensitive group and the Wolf Kishner reaction won't happen in the presence of a base sensitive group, citing $\...
- 1
2
votes
1
answer
99
views
Difference between change of enthalpy of neutralization between copper and manganese carbonate
I was doing a calorimetry experiment to calculate the change in enthalpy during neutralization reactions between metal carbonates and hydrochloric acid. I experimented with 5 metal carbonates: ...
CommunityBot
- 1
-4
votes
0
answers
19
views
Phosphate buffer saline with different pH values [closed]
I would like to know with which reagent we can decrease the pH of the potassium phosphate buffer saline?
- 4,545
5
votes
0
answers
11k
views
Reaction between sodium bicarbonate (baking soda), isopropyl alcohol, and acetic acid (vinegar)?
I observed this reaction by playing around with vinegar and baking soda and I do not completely understand it.
Everyone knows that baking soda (sodium bicarbonate) and vinegar (acetic acid) go crazy ...
- 6,722
0
votes
2
answers
98
views
How does the concentration of H+ ions in HCl change as the pH changes? [closed]
I am helping my friend's 16 year old prepare for her GCSE chemistry exam. This question was on an AQA GCSE Chemistry past paper but I do not know the year and could not find a markscheme for it on the ...
- 40.2k
-1
votes
0
answers
45
views
Unknown oily substance forming during reaction of concentrated vinegar and calcium carbonate
I was attempting to produce calcium acetate by mixing concentrated vinegar (bought online) and calcium carbonate (sourced from wood ash) and ran a small scale test in a beaker before I reacted the ...
0
votes
0
answers
31
views
Secondary alkyl halides and strong base: Sn2 vs E2
I got this question from the PYQs of a college entrance exam. According to the answer key, 4-chloro-3-methylpent-1-ene reacts with NaOH in water to give 4-hydroxy-3-methylpent-1-ene via the SN2 ...
1
vote
1
answer
164
views
Why are bases corrosive?
If I understand correctly, an acid corrodes things because the hydronium ion attracts electrons away from whatever it is reacting with. Do bases corrode things in a similar manner? with the metal ...
- 32.5k
-2
votes
2
answers
75
views
Reaction between copper rod and carbon rod in hydrochloric acid [closed]
The situation is this: a copper rod and a carbon rod, touching each other, are submerged in HCl(aq). We're asked to describe the reaction that occurs, but as far as I can see, there's no reaction? The ...
- 28.3k
4
votes
0
answers
224
views
Exchange of Fluorine to Oxygen for Fluorophosphonic acid by silylating agents or other methods?
[Warning, long post!]
Dear all,
I am confronted with a seemingly easy transformation. I want to remove a fluorine atom at a fluor phosphonic acid salt. The usual method to achieve this is the basic ...
CommunityBot
- 1
-1
votes
0
answers
56
views
Is there intramolecular H-bonding in 2-hydroxybenzonitrile?
Is there an intramolecular hydrogen bonding in 2-hydroxybenzonitrile? If so, then the $\mathrm pK_\mathrm a$ order should be meta > ortho > para but the actual order is meta > para > ortho....
- 4,545
-2
votes
0
answers
55
views
4 nitro groups on benzene [duplicate]
I was just wondering if there exists a phenol having 4 nitro groups. I tried searching the internet but couldn't find anything. If it exists what all features should it possess, and will it be more ...
- 4,545
1
vote
0
answers
29
views
Trends in pKb for both acetic acid and water
I am trying to rationalise a result that I have recently measured in the lab. I'm measuring the pKb of different compounds in anhydrous acetic acid, using the procedure outlined in this paper (https://...
- 11
1
vote
3
answers
6k
views
What happens to acids/bases left out overnight?
I conducted a titration experiment a few days back and was unable to neutralize the solution in time, so I had to leave the solutions of HCl and NaOH out overnight in order to use them the next day. ...
5
votes
1
answer
57
views
How to make a thin layer of crystalline barium titanate on copper substrate?
Is it possible to create a thin $\ce{BaTiO3}$ crystal layer on a copper plate by putting the plate in a beaker, pouring in heated hydrofluoric acid that has been saturated with $\ce{BaTiO3}$ powder ...
- 185
0
votes
1
answer
74
views
Hydrogen–deuterium exchange in 1,4-benzoquinone
Problem
Find number of deuterium exchanges in the following compound.
Solution
Question
I have been taught that hydrogen attached to the carbon which is directly or indirectly in conjugation with ...
- 72
0
votes
1
answer
41
views
pH in a buffer of Glycin and HCl
I am struggling with a task. I have the amino acid Glycin with pKa1=2,3 and pKa2=9,6.
I have 1.0 liter 0.20 mol/L solution of glycin. I add 0.1 liter 1 mol/L HCl solution. What is the pH in this ...
- 40.2k
-2
votes
1
answer
56
views
Is it possible to calculate the theoretical rate of reaction?
I am conducting an experiment where I will be changing concentration (0.2 mol/dm3, 0.4 mol/dm3, 0.6 mol/dm3, 0.8 mol/dm3, 1.0 mol/dm3) and seeing how that affects the rate of reaction for a reaction ...
- 3,191
-2
votes
1
answer
36
views
Is HCl in salt form reactive with metallized aluminium plastic film? [closed]
I’m in the process of packaging an amino acid that contains HCl in salt form. The mixture is 60% base and 40% HCl salt.
Will this react to metallized aluminium plastic?
- 32.5k
4
votes
2
answers
1k
views
Why do organolithium and organomagnesium compounds react differently with CO2?
My textbook doesn't say anything about this but does say that on addition of organolithium compounds to carbon dioxide, they give ketones and not carboxylic acids like grignard reagents. This has been ...
- 57.1k
10
votes
4
answers
8k
views
What is the real pKa of water?
What is the $\text{p}K_\text{a}$ of water? A simple google search yields the value $15.74$, but this site and this paper say it's $14.0$.
According to my understanding, the correct answer should be $...
- 2,163
-3
votes
1
answer
63
views
Why are alcohols considered slightly basic (based on pKa values)?
I understand why it makes sense for an alcohol to be slightly basic given the hydroxyl group and the electron-donating properties of the alkyl chain. But I'm a bit confused as to why it's the case ...
- 2,163
-2
votes
1
answer
44
views
Hydrolysis of $A_3B$ type weak acid-weak base salt
I know the formulae for weak acid-weak base salt of AB type. A peculiar question made me ask this. Do the formula for derived for AB type also hold for A3B type sal.
For example:
This is the question, ...
- 41.5k
13
votes
2
answers
2k
views
Could ammonium azanide exist?
In my first high school chemistry class, I misremembered nitrate as being $\ce{NH2-}$, rather than $\ce{NO3-}$, and wrote down a formula for "ammonium nitrate" that was $\ce{NH4NH2}$ (rather ...
- 37.7k
0
votes
2
answers
59
views
How do you identify an organic base?
Problem:
Solution:
The molecules with red crosses underneath them are considered organic bases.
Question:
From my understanding an organic base has an atom with a lone pair of electrons. Doesn't ...
- 4,545
2
votes
1
answer
3k
views
Order of lewis acidity for BBr3, BCl3, BMe3, BH3, BPh3?
In case of $\ce{BCl_3}$ vs $\ce{BH3}$, which one is the controlling factor?
1) Is it p-pi p-pi interaction in $\ce{BCl_3}$ that makes it weaker than $\ce{BH3}$?
2) Or is it the -I effect of $\ce{Cl}...
CommunityBot
- 1
-2
votes
1
answer
103
views
Can phosphorous penta hydroxide [P(OH)5] exist? [closed]
I was looking at the oxyacids of Phosphorous and it is given that (in Wikipedia article of "Phosphorous acid"), some of these acids (Eg: $H_3PO_2$ and $H_3PO_3$) exist in a dynamic ...
- 4,545
0
votes
1
answer
57
views
Change in pH/acidity of vinegar after adding aqueous NaCl
There's a question in my (grade 10) textbook asking to determine what will happen to the pH/acidity of vinegar if a solution of sodium chloride in distilled water is added to it drop by drop. The ...
- 29.8k
-5
votes
1
answer
70
views
Find the pH of a solution obtained by mixing 100 ml 0.1m Na3PO4 and 100 ml 0.1 M NaH2PO4. Given that H3PO4: [Κα₁ = 10^-4, Κα₂ = 10^-7, Каз = 10^-11] [closed]
So, my query is that since NaH2PO4 is a weak acid, and Na3PO4 is a basic salt, wouldn't they react? Another theory was that since NaH2PO4 is a weak acid and Na3PO4 is a salt of strong acid and NaH2PO4,...
- 28.3k
13
votes
1
answer
517
views
What is the structure of trifluoromethanesulfonic acid in the gas phase?
During an interesting discussion in our group’s seminar, the question arose what actually causes trifluoroacetic acid to be a much better nucleophile than trifluoromethanesulfonic acid. Part of the ...
- 4,545
0
votes
0
answers
56
views
What is happenning with that single hydrogen in Phosphorous acid?
As an oxyacid, Phosphorous acid intuitively should have the structure
since the hydrogens should be on the oxygens.
However, the major form of this acid is actually
with the hydrogen attached to the ...
- 101
1
vote
0
answers
25
views
Aquatic chemistry, pH and alkalinity
Hope you can help me with an aquatic chemistry question.
I have different types of water of different pH and alkalinity.
pH, alkalinity, HCO3 and CO2 concentrations are known.
I need to calculate the ...
- 11
-5
votes
1
answer
86
views
Does hydrogen chloride gas react with metals?
I searched and couldn't find any reactions with $\ce{HCl (g)}$ as a reactant, only with the acid in the aqueous phase ($\ce{HCl (aq)}$). Do metals react with $\ce{HCl}$ gas to form hydrogen?
- 57.1k
0
votes
3
answers
402
views
Can salt and water be obtained from a reaction between a gas and an acid?
Is it possible to get salt and water (neutralization reaction) by reacting a gas and an acid?
I don't know if it's possible or not. I'm unable to find any examples in this regard.
Would anyone be ...
- 57.1k
1
vote
0
answers
78
views
Why doesn't acid dissociation always have K>1?
Acid dissociation is usually exothermic, and it has an increase in entropy, so the change in Gibbs free energy should be negative. So why isn't always $K_\mathrm{a}>1$ in accordance with $\Delta G^...
- 21.7k
19
votes
1
answer
4k
views
How can benzaldehyde have a pKa of 14.9?
There are numerous websites out there which claim that the pKa of benzaldehyde – C6H5CHO – is 14.90. (Just do a Google search for benzaldehyde pka to see what I ...
- 4,545
2
votes
3
answers
14k
views
Reaction of concentrated nitric acid react with metallic lead?
Here is my work:
Concentrated $\ce{HNO3}$ should first decompose into $\ce{NO2}$, $\ce{H2O}$ and $\ce{[O]}$. Nascent oxygen should combine with $\ce{Pb}$ to form $\ce{PbO}$. Now $\ce{PbO}$ should ...
2
votes
1
answer
408
views
Why can Neutral Red (indicator) not test values below its pKa?
It is the only indicator I have found that does not test below its pka, and can't think of any reason for this.
Neutral Red has a pKa value of 6.8.
(
Reference 1,
Reference 2
),
but looking at its pH ...
- 12.1k
-1
votes
1
answer
86
views
What is the pKa of choline chloride?
I am looking for the pKa of choline chloride, which should be higher than 7 (around 10?), but I cannot find any reference value.
- 21.7k
-3
votes
1
answer
47
views
How does increased polarity of O-H increase acidity? Shouldn't it reduce it as bond strength increases?
A polar bond will be stronger than a relatively less polar bond. So how does increasing polarity of O-H bond ever increase acidity. Shoudn't it make it harder to release H+ and become less acidic.
- 85
1
vote
1
answer
55
views
Determination of the composition of the mixture based on acid-base titration
The solution can contain $\ce{HCl}$, $\ce{H3PO4}$ or $\ce{NaH2PO4}$
individually or in all possible combinations. An aliquot of
$25.00\,\text{mL}$ of this solution consumes $14.56\,\text{mL}$ of
$0....
CommunityBot
- 1
7
votes
2
answers
579
views
Question about the differences of white and grey NaH properties
We are having some problems with the next reaction in our lab. As you can see, is the sulfonylation of an indole in which we use NaH (60% dispersion in mineral oil) as a base. This reaction goes with ...
- 731
1
vote
1
answer
985
views
The effects of acetic acid on porous concrete brick and mortar joints
I mistakenly applied a patio cleaner containing acetic acid to my porous concrete facing brick thinking it was biocide. The concentrate solution has a pH of 3 and I diluted it to one part concentrate ...
CommunityBot
- 1
1
vote
0
answers
87
views
Acid base titration molar ratio [closed]
Consider the following neutralisation reaction:
$$ \ce{2HNO3 + Ba(OH)2 -> Ba(NO3)2 + 2H2O} \tag{1} $$
I would be glad for help in how to solve this problem with $c_1V_1 = c_2 V_2$, because the ...
- 220
6
votes
1
answer
7k
views
What is the pKa of methylamine
I completed a practice (not for marks) assignment for an organic chemistry course, and one of the questions asked for the pKa of methylamine.
I looked on PubChem, and it gave a result of $10.6$. ...
- 673
2
votes
3
answers
2k
views
Why do diacidic and triacidic alkalis dissociate in one step?
My book states that dibasic and tribasic acids dissociate in water in two and three steps respectively but for diacidic and triacidic bases it states that they dissociate in one step. I do not know ...
- 57.1k
0
votes
0
answers
57
views
Common Ion effect with sulphuric acid
Sulphuric acid dissociates completely (H2SO4 -> HSO4⁻ + H⁺).
Its product HSO4⁻ has a pKa of 1.92 which should then dissociate partially into SO4²⁻ and H⁺.
I was trying to find out the pH of a 0.05M ...
- 11
-2
votes
1
answer
114
views
Why is the ionic product of water also the equilibrium constant of dissociation of water?
This answer presents a derivation of the value of ionic product of water at $25^{\circ}\text{C}$.
The relation $K_\text{eq} = \operatorname{e}^{-\frac{\Delta_\text{r}G^{\circ}}{RT}}$ is used for the ...
- 41.5k
0
votes
0
answers
31
views
Question on electron density
I was working with ammonia ($\ce{NH3}$) and phosphine($\ce{PH3}$). Both have lone pair electron. But $\ce{NH3}$ is stronger base (Lewis base) than $\ce{PH3}$.
I was told by my instructor that it is ...
- 41.5k