All Questions
Tagged with equilibrium acid-base
357
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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 ...
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2
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255
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Why does this acid-base reaction occur?
My teacher told me about the reaction of sodium peroxide with water:
$$\text{Na}_2\text{O}_2 + 2\text{H}_2\text{O} \ce{->} \text{H}_2\text{O}_2 + 2\text{NaOH}$$
Now, the concentration of products ...
- 750
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Preparation of a HCN/NaCN buffer that has a pH of 9.8 and an osmotic pressure of 1.35 atm at 298 K
You are asked to prepare $\pu{2.0 L}$ of a $\ce{HCN/NaCN}$ buffer that has a $\mathrm{pH}$ of $9.8$ and an osmotic pressure of $\pu{1.35 atm}$ at $\pu{298 K}$. What masses of $\ce{HCN}$ and $\ce{NaCN}$...
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Why does the pH of the endpoint decrease when temperature of the titration is increased? [duplicate]
I was doing an experiment in chemistry class involving titrations. I would heat up different samples of vinegar and titrate them using NaOH. The trend that I found was how has temperature increase, ...
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pKa of acetic acid in pure NH3?
Acetic acid completely dissociates in liquid ammonia and I would like to know the $\mathrm{p}K_\mathrm{a}$ value for the acid in that solvent. Can anybody point me to a reference?
1
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967
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Dissociation equilibria of ammonium bifluoride in water
Ammonium bifluoride or ammonium hydrogen fluoride is a salt of a weak base and a weak acid.
The weak acid is because the second equilibria of $\ce{HF}$ written as:
$$\ce{HF + F- <=> HF2-}$$
and ...
- 421
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414
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Do Lewis acids and bases turn change colour of litmus
Well, the question is short. Can lewis acids and bases change the colour of a litmus paper? I can't seem to find the answer online (at least according to my high school level chemistry search history)....
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Why does the pH of a weak acid not increase by 1 when diluted by a factor of 10? [closed]
Strong acid pH increases by one unit when diluted by a factor of 10, but why do weak acids not?
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2
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Does carbonation permanently increase the acidity of soda water?
If you carbonate water, and then expose the resulting soda water to the atmosphere and wait until it goes completely flat, will the (former) soda water end up more acidic in final equilibrium than ...
- 121
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271
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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 ...
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pKa = pH for strong acid — strong base?
I have learnt that for a weak acid — strong base titration, $\mathrm{p}K_\mathrm{a} = \mathrm{pH}$ at the half equivalence point.
However, the same conclusion is not drawn when discussing strong acid —...
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1
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701
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Will a salt dissociate completely in water to give free ions?
I was reading salt hydrolysis of a salt made from strong acid and weak base. I came across the hydrolysis of $\ce{NH_4Cl}$. These reactions were mentioned
$$\ce{NH_4Cl + H_2O<=>NH_3 + HCl \tag{...
- 500
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What makes concentrated aqueous solutions of aluminium nitrate and aluminium chloride suitable to dissolve noble metals, specifically gold? [closed]
Aluminium nitrate is a strong oxidising agent and aluminium chloride acts as a Lewis acid. Also these solutions are claimed to have the abilities of aqua regia and therefore can dissolve noble metals.
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Does the acid dissociation constant takes hydrogen ions from water into account?
For the dissociation of a weak acid:
$$\ce{HA(aq)<=>H+ + A-}$$
To calculate $\mathrm{pH}$ of a weak acid, we use the expression: $$K_\mathrm{a}=\ce{\frac{[H+] [A-]}{HA}}$$
The $\ce{[H+]}$ has ...
- 500
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783
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Dissociation constant for Indicators
So I came across a question which asked to calculate the $\mathrm{pH}$ at which an indicator of given $\mathrm{K_{a}}$ would change colour. The solution was given in the following way
Since when the ...
