All Questions
12
questions
-5
votes
1
answer
113
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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
41
views
How to calculate the pH of a mixture of an acid with a buffered solution?
Being a physicist by training, having worked in software development for the last 10 years. Having heard my last chemistry lecture 15 years a go I am a bit lost in regards to how one can calculate the ...
- 111
-2
votes
2
answers
2k
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 ...
- 117
1
vote
1
answer
6k
views
Calculate pH of a buffer solution
Calculate the pH in a buffer prepared from $\pu{50 mL, 0.30 M}$ formic acid ($\ce{HCOOH}$) and $\pu{30 mL, 0.40 M}$ sodium formate ($\ce{HCOONa}$).
My way of solving:
$n_{\ce{HCOOH}} = 0.05 \times ...
- 1,095
8
votes
2
answers
1k
views
Why proton concentration is divided by 10⁻⁷?
I am reviewing the book Biochemistry Concepts and Connections by Appling, Cahill, and Mathews and I cannot understand why they divide by the hydrogen concentration by $10^{-7}$. Why not just leave it ...
- 191
0
votes
1
answer
665
views
What is the citric acid concentration, [HCit], in the lemon juice?
The pH of lemon juice is about 2.1. What is the citric acid concentration, [HCit], in the lemon juice?
I am given that $HCit \leftarrow \rightarrow H^+ + Cit^-$ and that $K_a = 8.4 \times 10^{-4}$.
...
- 209
-1
votes
1
answer
108
views
Redox - concentration cell
I'm studying galvanic cells and I've found a demonstration that lead me to an impossible result, so there must be a mistake, but I can't find what it is.
My problem is about concentration cells made ...
- 197
1
vote
0
answers
593
views
Why does [H3O+] of a buffer change very slightly when diluted?
I am confused as to why the [H3O+] of a buffer changes very slightly when diluted (at least in an intuitive sense).
Consider:
$\ce{HNO2 + H2O <=> H3O+ + NO2-}$
[$\ce{HNO2}$] = 0.45 M and [$\...
- 59
0
votes
2
answers
15k
views
Calculating concentration of H+ Ions using Ka Value [closed]
I have this homework question that I am a bit stuck on for an answer. If anyone could help that would be great.
Question:
For a $\pu{0.2M}$ $\ce{HNO2}$ solution ($\pu{K_a= 4.5 \times 10^{-4}}$) ...
- 121
2
votes
1
answer
5k
views
How many moles NH4Cl must be added to NH3 to create buffer with pH=9?
How many moles of $\ce{NH4Cl}$ must be added to $\pu{2.0 L}$ of $\pu{0.10 M}$ $\ce{NH3}$ to form a buffer with $\mathrm{pH}=9$? Assume the addition does not change the volume of the solution ...
- 1,398
2
votes
2
answers
47k
views
Finding new pH after NaOH added to buffer solution
I have a buffer containing 0.2 M of the acid $\ce{HA}$, and 0.15 M of its conjugate base $\ce{A-}$, with a pH of 3.35. I need to find the pH after 0.0015 mol of $\ce{NaOH}$ is added to 0.5 L of the ...
- 749
0
votes
1
answer
131
views
Ionic Equilibrium
Calculate the pH of a solution which contains 100mL of 0.1M $\ce{HCl}$ and 9.9mL of 1.0M $\ce{NaOH}$.
While calculating the concentration of $\ce{H+}$ ions, why shouldn't we consider the H+ ion ...
- 1