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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Does diluting the titration flask change the molarity
I was solving the following problem on a test and I thought the answer was A, but the answer is actually D. Below is the problem and my reasoning:
Answer choice B is clearly incorrect because the ...
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2answers
23 views
Solubility and pH
I was reading about antacids. It stated that in earlier times $\ce{NaHCO3}$ and a mixture of aluminium and magnesium hydroxide were used as antacids. In excess $\ce{NaHCO3}$ can make the medium ...
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0answers
21 views
Conductivity of aqueous solutions
Which $\ce{0.10 M}$ aqueous solution exhibits the lowest electrical
conductivity?
A) $\ce{HC_2H_3O_2_{(aq)}}$
B) $\ce{HNO_3_{(aq)}}$
C) $\ce{NH_4C_2H_3O_2_{(aq)}}$
D) $\ce{Ca(...
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1answer
23 views
Is the equilibrium constant related to concentrations
In an acid-base reaction, let K be the equilibrium constant and t the equilibrium position.
We learned that K is only affected by temperature, while t is affected by other factors including ...
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2answers
27 views
why is are weak acid-strong base and strong acid-weak base reactions irreversible?
In the case of both are strong, I can see why it's irreversible, because the acid is very willing to give a proton and the base is very willing to take one.
Now here are my 2 main questions:
1-in the ...
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0answers
15 views
Acid-Base: calculating concentration when pH is given [on hold]
Something I don't understand in these questions is, for example when a pH is given and it is said that you should calculate the concentration of a NaOH solution, why is the concentration calculated ...
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0answers
27 views
Why are strong acid-base reactions irreversible? [on hold]
With the condition that at least one of the reactors is strong so (strong acid/weak base) or (weak acid/strong base) or (strong acid/strong base), how do we know that they're not reversible.
Or in ...
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0answers
18 views
Contaminant aluminium(III) compounds in acidic soil [on hold]
I recently looked for aluminum source/contamination that migrates to agriculture soil. The toxic form of $\ce{Al}$ to plants is $\ce{Al^3+}$. Are there any of $\ce{Al}$-containing compounds (e.g. $\ce{...
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1answer
38 views
Compound, Ascorbic acid: What implies the dotted line? [on hold]
What implies the two dotted lines?
Why has the two carbon on the left side 3 free electrons? With C₆H₈O₆ not all carbon atom is connected.
What is the topic which describes how to read and understand ...
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0answers
21 views
Buffer Capacity Equation
Whilst doing buffer capacity, my lecturer presented us with the following equation for buffer capacity:
$${log(\frac{[salt] + x}{[acid] - x})} = 1$$
A task set by the lecturer is to rearrange the ...
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0answers
16 views
How much Sodium Bicarbonate (NaHCO3) do I need to add to specific volume of water to increase the pH by specific amount? [closed]
I'm trying to increase the pH of a nutrient solution for algae I'm attempting to grow. I suspect that my algae will grow at a higher pH than contaminants.
I want to raise the pH of a container of ...
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0answers
14 views
How do I make a 0.5 M citrate buffer at pH 4.5?
I need to make a citrate-sodium citrate buffer at 0.5 M concentration and pH 4.5. I calculated the molarities of the citrate and disodium citrate based on the Henderson Hasselbalch equation, using a ...
0
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0answers
42 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 ...
1
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1answer
22 views
Acid value of linseed oil
For this we weigh $\pu{1.015 g}$ of linseed oil which is dissolved in alcohol. 3 drops of phenolphthalein (pH indicator) are added and a solution of potassium hydroxide of concentration $C = \pu{9.5e-...
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0answers
118 views
Sulfuric hydrofluoric acid? [duplicate]
Comment on https://www.youtube.com/watch?v=Hxh92s5mIho showing it is the effect of sulfuric hydrofluoric acid..
Is it a effect of sulfuric hydrofluoric acid?
2
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0answers
20 views
Confusion about prioritizing functional groups in case of poly functional organic compounds
According to Wikipedia,
sulfonic acid $(\ce{-SO3H})$ is comparatively stronger than carboxylic acid $(\ce{-COOH})$.
Then why is sulfonic acid lower in priority than carboxylic acid (while naming poly ...
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0answers
13 views
Acid medium versus Basic medium characteristics in organic reactions [closed]
I am kind new in the study of organic reactions and I have collected some points to write differences between acid medium and basic medium:
Acid medium
1)favors strong oxizidation
2)favors ...
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0answers
16 views
Oxidation of a metal by an inorganic acid [closed]
What is the effect of particule size and temperature on the reaction of a metal and an inorganic acid? I need it for a paper that I have to hand in but I cannot find the answer anywhere and I haven't ...
1
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1answer
28 views
Can an iodine clock reaction work without using a strong acid?
I'm going to do an iodine clock reaction for a project and we had to submit the materials and safety sheets for the experiment a while ago. I thought I could do one by using hydrogen peroxide, sodium ...
1
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1answer
27 views
pH of very dilute acids
From doing some research on the site I have found that many people have posted about solutions of $\ce {HCl}$ where $\ce {[HCl]=10^{-8} mol dm^{-3}}$
Here they are able to deduce
$$\ce{[H^+] =\frac{[...
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1answer
21k views
Is Sulfuric hydrofluoric acid a real thing? [closed]
I saw a video on social media of a person disappearing into air when exposed to Sulfuric hydrofluoric acid vapours. I don't have much knowledge in chemistry. Is this possible combination.
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0answers
21 views
Why do some cations and anions interact with water to form corrresponding acids and bases(hydrolysis)? [duplicate]
I have seen in my textbook that on cations/anions formed on ionization of salts either exist as hydrated salts in aqueous solutions or interact with water to reform corresponding acids/bases depending ...
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1answer
36 views
Acidic, Basic, and Neutral Medium
So I'm new to this concept and I can't find any proper explanation to this. What does it mean for a reaction to occur in an acidic, basic, or neutral medium?
1
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1answer
39 views
What are good examples of questions that make college students think about chemistry concepts? [closed]
I am teaching the second semester of general chemistry at the college level. The course tends to get bogged down in calculations, and sometimes we forget about the big picture and what is going on at ...
1
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2answers
44 views
Calculating dissociation degree from pH and Ka without given initial acid concentration
Is it possible to calculate the dissociation degree (DD) from pH and Ka without directly been given the initial acid concentration?
I found the following formula:
$$\text{DD} = \frac{K_\mathrm{a}}{...
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0answers
28 views
What is the maximum concentration of HNO3 (nitric acid) which may be handled outside of a hood?
Commercial stock solutions of HNO3 (nitric acid) are usually 70% w/w, and according to several MSDSs (e.g. here), it is dangerous to inhale it:
Symptoms/effects after inhalation : Irritation ...
0
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2answers
64 views
Which of the following is the most acidic salt?
A 0.1 M solution of which salt is most acidic?
(a) Aluminum(III) nitrate $\ce{Al(NO3)3}$;
(b) Magnesium(II) bromide $\ce{MgBr2}$;
(c) Sodium bicarbonate $\ce{NaHCO3}$;
(d) Sodium formate $\...
11
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2answers
151 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 ...
2
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1answer
55 views
“Don't pour oil into lye, pour lye into oil”
I was making soap last weekend and I got distracted, and thence I put too much lye into my oils blend. Basically, the whole soap paste is unusable to make soap because the cure will never be enough to ...
5
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2answers
96 views
Why can the acidic strength between H2S and HCl be explained on the basis of electronegativity but H2S and H2O can't?
Consider simply aqueous solutions of $\ce{H2S}$ and $\ce{HCl}$ . It is pretty much known that $\ce{HCl}$ is stronger than $\ce{H2S}$ in water. The reason behind that first is the electronegativity of ...
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0answers
35 views
Nucleophile vs base and Electrophile vs acid [closed]
How we will figure out that a given compound will behave as nucleophile or base ? Same problem for electrophile and acid.
By the way I have already seen a similar question though I didn't find it ...
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1answer
53 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
32 views
Acidic tendency of copper(II) ion vs. calcium(II) ion
In my Chemistry textbook, a table is shown wherein ions originating in various salts are categorised according to their acidic or basic tendencies. Among others, $\ce{Cu^2+}$ and $\ce{Ca^2+}$ are ...
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0answers
32 views
Why is C2H5 a stronger +I group than CH3?
While reading about the basic character of amines, I came across a note which said that $\ce{CH3-CH2-NH2}$ was more stable than $\ce{CH3-NH2}$ as $\ce{C2H5}$ was a stronger +I group than $\ce{CH3}$.
...
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0answers
20 views
Can an interaction be considered both hard-hard and soft-soft?
The $\ce {B-F}$ bond can be described as having both a large ionic and a large covalent character$\ce {^1}$, with the AIM charges on $\ce {F}$ and $\ce {B}$ being $\ce {-0.81}$ and $\ce {+2.43}$, ...
4
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1answer
81 views
Why are amidines more basic than amines?
Amidines can be thought of as carboxylic acid derivatives with the carbonyl oxygen replaced by a nitrogen and hydrogen atom; amidines exhibit conjugation.
Amidines are more basic (less acidic) than ...
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2answers
49 views
How to balance this redox reaction taking place in a basic medium?
How to balance this reaction which is taking place in a basic medium?
$$\ce{Al + MnO4- -> MnO2 + Al(OH)4-}$$
My Attempt
Reduction half reaction:
$$
\begin{align}
\ce{4 H+ + MnO4- + 3 e- &-&...
2
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1answer
45 views
Molecular orbital explanation of why the protonation of the oxygen atom makes a carbonyl group more electrophilic
I was working on nucleophilic addition reactions to the carbonyl group (namely, hemiacetal formation) when I came across the following explanation for the use of acid catalyst and how it increases ...
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0answers
16 views
Which is more acidic 2-Ethylbenzoic acid or 2-Methylbenzoic acid?
Both will undergo Ortho effect
But as ethyl group is more bulkier it will show more Ortho effect to -COOH group as compare to methyl
Is the above reason is correct?
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1answer
46 views
Why Does 0.10 M Dihydrogen Phosphate Dissociate Rather than Hydrolyse in a Neutral Solution of Water?
Dihydrogen Phosphate has a Ka of 6.2x10^-8, yet it seems to form solutions with an acidic pH when it is in water. Why is that? Shouldn't it dissociate back to phosphoric acid and form a basic ...
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0answers
35 views
Calculating pH of extremely dilute HCl solution [duplicate]
The $pH$ of a $10^{-8} M$ (M = moles per liter) $HCl$ solution is to be calculated. The plan is to calculate the ionization constant ($K_a$/acidity) first, and then derive the $pH$.
However, as the ...
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0answers
74 views
How do I neutralize 1.2 % muriatic acid (134.4 liters) residue with 99 % caustic soda flakes?
I cleaned my commercial water purification system with muriatic acid but I overdid it. Now there is excess muriatic acid residue. I used 6 liters of 29 % muriatic acid and further reduced with 33.6 ...
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0answers
40 views
Topic in Salt hydrolysis that I couldn't understand
Salts can be made up of all combination S of ( SA ,WA) and (SB , WB)
I understand how to deal with salts of strong acids with both strong and weak bases and also of strong bases with weak and strong ...
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1answer
72 views
Water as a “Harmful Acid”
Apologies for the question which is far below the brilliance of the minds on this page. I have an A-Level in Organic Chemistry but I'm tying myself in knots with this one.
I'm a magician looking to ...
1
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1answer
22 views
Why must a buffer solution contain both a weak acid and a salt solution of its conjugate base?
Doesn’t the weak acid dissociate to produce the conjugate base on its own?
I understand that when a strong base is added to the buffer solution, the hydroxide ions will react with the hydrogen ions ...
2
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1answer
37 views
Acidity comparison between cyclopropene and cyclopropane
There many sources on the internet saying that cyclopropane is more acidic than cyclopropene because the conjugate base in latter would have antiaromaticity which would destabilize it.
But in this ...
1
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0answers
28 views
Why aren't primidone's lactam groups acidic?
I understand that 5,5-disubstituated derivates of barbituric acid only show lactam-lactim tautomerism opposed to the lactim-lactam and keto-enol tautomerism of barbituric acid, hence the 5-mono and 5,...
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0answers
39 views
pKa Conceptual Questions [closed]
If anyone could clear up some of this conceptual confusion, that would be much appreciated.
Is $\mathrm pK_\mathrm a$ an intrinsic property of a molecule? Or extrinsic? A property is extrinsic if it ...
5
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1answer
109 views
Using thermodynamics to predict the acid-base character of fluoride ion in water
I was working through the end-of-chapter exercises of the acid-base chapter in Shriver's Inorganic Chemistry when I came across the following problem:
4.7. The effective proton affinity $\ce{A^{'}_{...
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2answers
40 views
Does concentration or pKa define acid strength?
For example, is 3M HCl a stronger acid than 1M HCl?
I would reason that the concentration of an acid/base does not influence its strength. Strength is determined by the pKa, and, as per Le Chatelier'...
