All Questions
17
questions
-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,...
2
votes
1
answer
103
views
Equilibrium Solubility of CO2 in Aqueous Solution and its Dependence on H3O+ Concentration
The equilibrium solubility of $\ce{CO2}$ in an aqueous solution is given by three chemical reactions:
$$
\begin{align}
\ce{CO2(g) &<=> CO2(aq)}\label{rxn:R1}\tag{R1}\\
\ce{CO2(aq) + H2O &...
0
votes
0
answers
550
views
Adding aluminum sulfate to neutralize an aqueous solution of sodium silicate with pH of 12.6
How much aluminum sulfate do I need to add to an aqueous solution of sodium silicate to neutralize the solution (pH from 12.6 to 7)?
For a water treatment school project, we remove sodium silicate ...
- 173
0
votes
1
answer
271
views
Why are some weak acid equilibrium approximations invalid in very dilute solutions?
Using two approximations for the dissociation of a weak acid, we can write
$$K_\mathrm{a}= \frac{[\ce{H+(aq)}]^2}{[\ce{HA(aq)}]}$$
One of these two approximations we use is that the concentration of ...
- 209
-1
votes
1
answer
512
views
An equilibrium question involving mixing equal volumes of HCl and H2SO4
Question: Calculate the concentrations of H3O(+) and SO4(2-) in a solution prepared by mixing equal volumes of 0.2M HCl and 0.6M H2SO4. (Ka1 for H2SO4 is very large, and Ka2 for H2SO4 is 1.2E-2)
Here ...
- 65
6
votes
2
answers
208
views
Protons and osmotic potential
In a hypothetical enclosed membrane only permeable to water (including hydronium), where inside the pH is lower than the outside, would water move inside?
- 61
-2
votes
2
answers
2k
views
pH of strong acid weak acid mixture [closed]
Question: $\ce{H2S}$ ($\pu{0.1M}$; $K_\mathrm{a} = 1.2×10^{-20} $) and $\ce{HCl}$ ($\pu{0.3M}$) with same volume are mixed together. What is the resultant $\mathrm{pH}$?
My approach:
Let the volume ...
- 117
3
votes
0
answers
97
views
Common ion effect
Let $\ce{HA}$ ($x$ molar) be a strong electrolyte and $\ce{HB}$ ($c$ molar) — weak electrolyte. As $\ce{HA}$ is strong electrolyte, it dissociates completely:
$$
\begin{array}{lcc}
\ce{&HA &-&...
- 117
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
vote
1
answer
178
views
Confusion about the ICE table
Calculate the pH of a $\pu{2M}$ $\ce{H_3PO_4}$.Calculate the equilibrium concentrations of $\ce{H_3PO_4 , H_2PO_4^{-} , HPO_4^{2-}}$.
First equation:
$\ce{H_3PO_4 <=> H^{+} + H_2PO_4^{-}}\ \ \...
- 141
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
1
answer
273
views
Why doesn't hydroxide concentration equal concentration of carbonic acid and bicarbonate in a sodium bicarbonate solution?
To find the pOH of solution of $\pu{0.42 M}$ of $\ce{NaHCO3}$, given a $\ce{Kb}$ of $\pu{2.4E-8}$, my solution manual does the following steps:
Reaction is similar to : $\ce{HCO3- + H2O <=> ...
- 2,853
5
votes
3
answers
11k
views
Why is Ka constant when volume is increased?
The following graph shows $\ce{Ka}$ vs ${V}$ (Volume) at constant temperature, as ethanoic acid is diluted:
However, I thought it would instead produce the following graph (see below).
$\ce{Ka=[...
- 2,853
0
votes
1
answer
15k
views
Finding OH- concentration given the H+ concentration - diverse methods
There was this exercise which asked to find the OH- concentration given the H+ concentration, i firstly calculated the pH as -log[H+], did 14-pH to find the pOH and then did 10^(-pOH) to find the ...
- 21
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