All Questions
518
questions
-1
votes
0
answers
32
views
Algebraic method for modelling sodium acetate in solution
For a solution of sodium acetate ($NaA$), I want to find the concentrations of $H^+$, $OH^-$, $HA$ and $A^-$ via the algebraic method, being the total concentration of $NaA$ $C_A=0.25~\text{M}$, the ...
- 337
1
vote
1
answer
41
views
H+ concentration of the mixture of a strong and weak acid
I reviewed the complete solution (hand-written) to the problem at Calculation of the pH of a mixture of a strong acid and weak acid.
My question is why it is okay to apply the K1 value for the weak ...
- 11
2
votes
2
answers
115
views
Why would the theoretical pH not match the measured pH when performing a titration of NH4OH with HCl?
I ran a weak base - strong acid titration experiment using an automatic titrator. I started with an aqueous ammonia stock solution (somewhere in the range of 0.1 - 2.5 wt.%) that was left open to ...
- 39
-5
votes
1
answer
45
views
Why should the pH change when I add sodium hydroxide to water? [closed]
I am a student and I am trying to understand the concept of pH.
If I add pure $\ce{NaOH}$ in water, it leads to the formation of $\ce{OH-}$ ions in the water. But this shouldn't lead to any change in ...
3
votes
0
answers
27
views
Non-binding buffer at pKa of roughly 6 that dissolves in ethanol?
I'm trying to find a proper buffer for my experiment, which I'd appreciate some suggestions on. I have a solution in which I want to measure the concentration of magnesium ions using a fluorescent ...
- 31
1
vote
3
answers
176
views
pH at maximum concentration of a certain species (Phosphoric acid) [closed]
I am trying to find the pH at which $[H_{2}PO_{4} ^{-}]$ is maximum by only knowing the pKas.
I have tried to derive an equation using kinetics but it failed [1].
After taking a look at the Sillén/...
- 31
1
vote
2
answers
199
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 ...
- 247
-2
votes
1
answer
49
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, ...
- 93
0
votes
1
answer
82
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 ...
- 11
-5
votes
1
answer
113
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,...
1
vote
0
answers
28
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
0
votes
2
answers
147
views
Can carbonic acid form a salt with pH < 7?
Please read edit before answering
Background
I am currently studying in 10th grade. This question appeared in my science exam -
Which acid does not form an acidic salt?
Phosphoric acid
Carbonic acid
...
-4
votes
1
answer
61
views
Is it possible to make acids and bases in amphiprotic solvents other than water [closed]
In such solvents, could there be chemicals which could donate/accept protons, and if so could their solutions display acidic/basic properties?
- 1
-3
votes
2
answers
310
views
Can a multimeter be used to measure PH?
I would like to feed my garden a solution of water and Trisodium Phosphate (TSP), but I am uncertain of the correct amount of TSP to water ratio. Too acidic or too basic of a solution can harm my ...
- 874
0
votes
2
answers
171
views
dilution and pH and pOH
The question is: given a $10$ ml solution with pH = $12.3$, which is then diluted to a $100$ ml solution, find the pH of the new solution. My attempt was as follows:
[H$_3$O$^+$] = $10^{-12.3}$, and $...
- 109
3
votes
1
answer
163
views
Are there LCMS compatible buffer systems available for the high pH range 12-14?
I want to perform chemical stability studies for different pH Values. To achieve pH Values from 1 to 6 I can prepare solutions with trifluoric acid and formic acid and ammonium formate and acetate. I ...
- 799
-4
votes
1
answer
171
views
At 80 °C a solution having pH = 7 is? [closed]
When I came across this question I couldn't understand whether, they are asking the nature of solution at 25 °C which has pH = 7 at 80 °C or nature of solution at 80 °C which has pH = 7 at 25 °C ?
...
-2
votes
3
answers
674
views
Can pure hydronium exist?
Can pure hydronium exist? If not, why not? It seems to me (and I am no chemistry expert) like pure hydronium should have the theoretical maximum acidity or minimum pH that a substance can reach.
Can't,...
3
votes
1
answer
98
views
Why is pH the most commonly known acidity scale when there are more intuitive ones?
Consider the switch from $$\operatorname{pH} = -\log_{10}\left(\left[\ce{H3O+}\right]\right)$$ to $$\operatorname{acidity} = +\log_{10}\left(\frac{\left[\ce{H3O+}\right]}{\left[\ce{OH-}\right]}\right)$...
- 139
-2
votes
1
answer
94
views
Creating Chloramines
I'm currently conducting some testing related to indoor pool environments.
Here I believe, airborne chloramines are responsible for stress corrosion cracking in austenitic stainless steels.
...
- 65
-2
votes
1
answer
92
views
Calculate the pH of a buffered solution after adding strong acid [closed]
Calculate the pH of a solution formed by the addition of $0.0020$ moles of $\ce{HCl}$ to $\pu{100.0 mL}$ of $\pu{0.200 M}$ $\ce{CH3NH2}$/ $\ce{0.100 M CH3NH3Cl}$.
$K_\mathrm{b}(\ce{CH3NH2})=4.4\times ...
- 33
1
vote
0
answers
410
views
Determine the pKa of a diprotic acid by titration (if pKa1 is similar to pKa2)
Determining the acidity constants of a diprotic acid (in my case, tartaric acid) by titration with NaOH and pH-meter is not possible if pKa2 - pKa1 < 2.
This is because there are no "pH jumps&...
- 109
1
vote
2
answers
290
views
pH of a mixture of a weak acid and a different (non-conjugate) weak base
Let's say I have 1000 ml 1 M acetic acid ($\mathrm{p}K_\mathrm{a}$ = 4.76) and add 1000 ml 1M aniline ($\mathrm{p}K_\mathrm{aH}$ = 4.65). To what proportion is aniline protonated?
1M acetic acid has a ...
- 51
-1
votes
1
answer
55
views
How to find the added volume $V_e$
We have a volume $V_A$ of a solution of $\ce{CH3COOH}$ acid, its molar concentration is $C_A$ and it has $pH_0=3,4$, we add a volume of $V_e$ from distilled water to it, in this case it has $pH_0'=3,7$...
-1
votes
1
answer
75
views
pH of a solution from mixed solution
I am not a chemistry student. I have a problem with my preserved food. I am afraid that the pH is not below 4.6 for it to safe to eat. I want to check the pH of the food but it has small amount of ...
- 11
1
vote
1
answer
216
views
Henderson-Hasselbalch equation and degree of dissociation
Is it possible to evaluate the degree of dissociation in unbuffered solutions, through the Henderson-Hasselbalch equation?
For example: place acetic acid in a sodium hydroxide solution. After the ...
- 127
6
votes
1
answer
169
views
How to explain the acidity difference between these β-diketones?
In DMSO, pentane‐2,4‐dione (1) and 1,3‐diphenylpropane‐1,3‐dione (2) possess nearly identical $\mathrm{p}K_\mathrm{a},$ whereas 1‐phenylbutane‐1,3‐dione (3) is almost 1 $\mathrm{p}K_\mathrm{a}$ unit ...
- 128
-1
votes
1
answer
148
views
pH and degree of dissociation of drugs
I have a doubt, i hope not so stupid.
Suppose we consider a buffer solution of acetic acid/acetate at pH = pKa = 4.76 and we add aspirin (pKa = 3.5): given that the pH of the solution is higher than ...
- 127
-3
votes
1
answer
132
views
Even in an acidic solution with a pH equal to 0, there are only 1 mol/L H3O+ ions, while there are approx. 54 mol/L water molecules
I find this sentence in my high school chemistry book to be confusing:
"Even in an acidic solution with a pH equal to 0, there are only 1 mol/L H3O+ ions, while there are approx. 54 mol/L water ...
- 157
-2
votes
1
answer
143
views
What's the pH of a solution knowing only pKa, mass and volume? (no molecular mass known)
Is it possible to calculate the pH of a given solution knowing only the pKa (but not the structure of the acid, i. e. its molecular mass), its mass and the volume of the solution? E. g. What is the pH ...
