All Questions
Tagged with aqueous-solution inorganic-chemistry
252
questions
4
votes
1
answer
95
views
Why is my Ni or Fe cathode blackening and pores getting blocked during alkaline (6 M KOH) electrolysis?
I am conducting an electrolysis process for hydrogen $(\ce{H2})$ and oxygen $(\ce{O2})$ generation using a $\pu{6 M}$ $\ce{KOH}$ alkaline solution.
During the process, I have observed that my cathode ...
- 41
2
votes
0
answers
38
views
Salts solubility and speciation calculations using PHREEQC
I am collecting data from literature for CO2 solubility in aqueous solutions. These are usually synthetic brines and are reported as molalities or wt% of salts or salt mixtures (I have NaCl, KCl, ...
0
votes
1
answer
123
views
What reaction takes place when ammonia and sulfur dioxide are introduced into barium chloride solution?
What reaction takes place when gaseous $\ce{NH3}$ and $\ce{SO2}$ are introduced into $\ce{BaCl2}$ solution and an insoluble white solid is produced?
I think that the white solid could be $\ce{BaSO4}$ ...
- 133
2
votes
1
answer
67
views
Does solubility product dictate predominant precipitate from the solution with several ionic compounds?
While removing temporary hardness through boiling, magnesium bicarbonate will give $\ce{Mg(OH)2}.$ $\ce{Mg(OH)2}$ predominates over $\ce{MgCO3}$ as the solubility product $K_\mathrm{sp}$ of $\ce{Mg(OH)...
- 23
13
votes
3
answers
2k
views
Do electrons really hang around the electrode while ions go take a swim?
This answer to this post addresses "what happens if you dip a single zinc electrode into some electrolyte solution." It explains that
However, though the zinc ion can diffuse through the ...
- 22.5k
1
vote
1
answer
107
views
Why does balancing the oxidation of dichromate(VI) to chromium(III) require six iron atoms?
The problem:
Balance the following chemical equation using oxidation numbers:
$$ \ce{Fe^2+ + Cr_2O_7^2- -> Fe^3+ + Cr^3+} $$
What I have tried:
$$\ce{\overset{+II}{Fe}^{2+}(aq) + \overset{+VI}{Cr}...
- 133
2
votes
2
answers
145
views
In an unsaturated solution, is the product of ions still equal to Ksp?
Suppose I have a solution of a sparingly soluble compound, and consider its solubility in g/L. If I have less g/L of solution than that amount, it means the solution is unsaturated, but what happens ...
- 67
1
vote
0
answers
31
views
Estimation methods for temperature evolution of a high $\Delta H_{mix}$ dilution ($\ce{KOH}$ in water)
Question up front: Can temperature evolution in solutions be short-hand-estimated by simple state based calculations - with reasonable expectations of precision? (+/- 10° C)
I am trying to calculate ...
- 2,805
1
vote
2
answers
454
views
What is the hydrated diameter of a lithium ion？
When salts dissolve in water, the anions, cations, and strongly polar water molecules undergo hydration reactions, resulting in the formation of hydrated ions with a specific number of coordinated ...
- 31
0
votes
1
answer
475
views
Why does balancing the reduction of dichromate(VI) to chromium(III) require four water molecules among the products?
Problem
Balance the following chemical equation using oxidation numbers:
$$\ce{Cr2O7^2–(aq) + HNO2(aq) –> Cr^3+(aq) + NO3–(aq)}$$
Solution (in Swedish)
$$\ce{\overset{+VI}{Cr}_2O7^2–(aq) + H\...
- 133
-1
votes
1
answer
98
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what will happen if we add lithium cobalt oxide into water?is it true that molecule will break and lithium will make LiOH and CoO2? [closed]
I have tried to dissolve powder coated on cathode of lithium ion batteries.
0
votes
1
answer
308
views
What is ionic reaction equation for reaction between carbon dioxide and limewater?
Write the ionic reaction equation for the reaction
\[\ce{Ca(OH)2(aq) + CO2(g) <=> CaCO3(s) + H2O(l)}.\]
I first wrote the complete ionic equation as such:
\[\ce{Ca^2+ + 2 OH^- + CO2 <=> ...
- 133
0
votes
0
answers
21
views
Dissolution of portlandite, calcite/CaCo3 phase and C-S-H due to high pH
I would like to ask about the possibility of the partial dissolution, over curing time, of portlandite, CaCo3 and C-S-H phases due to high pH (12.5 - 13) of the lime-clay-water systems (lime-...
- 1
3
votes
1
answer
805
views
When NaOH ionizes in water, does the OH– react with the water molecules or with the hydronium ions from the dissociation of water?
NaOH in water becomes $\ce{Na+}$ and $\ce{OH-}$ ions. If it's a Bronsted Lowry base then the $\ce{OH-}$ ions will take $\ce{H+}$. But FROM where exactly - from the water molecules or from the ...
1
vote
1
answer
105
views
What is the maximum number of silver(Ⅰ) ions in one litre of a 0.003 M sodium sulfide solution?
What is the maximum number of silver(Ⅰ) ions that can be present dissolved in one litre of a $\pu{0.003 M}$ $\ce{Na2S}$ solution?
According to my book, silver(I) reacts with sulfide producing $\ce{...
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-2
votes
3
answers
130
views
What is the precipitation reaction?
I asked my teacher if the reaction
$$\ce{(NH4)2CO3 (aq) + MgBr2 (aq) <=> MgCO3 (s) + 2(NH4)Br (aq)}$$
can be considered a displacement reaction. She answered that it was a precipitation reaction ...
2
votes
0
answers
230
views
Why is it recommended to not store commercial sodium silicate solutions in direct sunlight, what are the effects of doing so and can it be modelled?
I regularly purchase aqueous sodium silicate solutions from commercial providers for my studies and note that a storage recommendation for all different grades (i.e. differing $\ce{SiO2 / Na2O}$ ...
- 500
0
votes
1
answer
652
views
Is calcium carbonate a Brønsted–Lowry base, a Lewis base, or both? [closed]
What type of base would $\ce{CaCO3}$ be in the following example:
$$\ce{CaCO3 + H2SO4 -> CaSO4 + CO2 + H2O}?$$
My understanding is that calcium carbonate cannot be a Brønsted–Lowry base because ...
- 69
-5
votes
1
answer
59
views
Why is 10 times phosphate-buffered saline more acidic (~6.9) than 1 time phosphate-buffered saline (~7.4)? [closed]
Recently, I've been told that similar pH shift (of about 0.5 units) was observed with 20 times NPS solution as well.
In case of NPS the authors provide the following recipe for the 20 times solution:
...
- 111
2
votes
0
answers
259
views
Is it always necessary to boil off H2S(g) to test for group III cations in qualitative analysis?
When a sample contains $\ce{Al^3+}$ ions (group-III), to test for its presence, before adding NH4Cl/NH3 solution do we need to boil off acidic H2S added earlier to check for the presence of group-ii ...
- 131
1
vote
1
answer
184
views
How to balance iodometric equations using ion electron method? [duplicate]
I found out the reductant, oxidant, oxidation half reaction, reduction half reaction; balanced ions (adding $\ce{H2O},$ $\ce{H+},$ electrons) and charges:
$$\ce{K\overset{-1}{I} + \overset{+2}{Cu}SO4 -...
0
votes
0
answers
682
views
Reaction of lead with acetic acid and hydrogen peroxide solution
My textbook says lead reacts with acetic acid when there is enough oxygen to oxidize lead:
$$\ce{2 Pb + O2 + 4 CH3COOH -> 2 Pb(CH3COO)2 + 2 H2O}$$
So, I added lead into mixed solution of acetic ...
- 677
1
vote
1
answer
153
views
Store Palladium Chloride in Solution
I have one gram of palladium chloride ($\ce{PdCl2}$) and I want to use very small quantities of it, in milligrams somewhere. It is not possible for me to get my hands on a scale that can measure that ...
- 111
0
votes
0
answers
418
views
Reaction of hydrogen peroxide with acetic acid and potassium permanganate
I conducted an experiment where I mixed hydrogen peroxide $\ce{H2O2}$, acetic acid $\ce{CH3COOH}$ and potassium permanganate $\ce{KMnO4}$ under vigorous stirring. The reaction hasn't stopped after 15 ...
user127378
-1
votes
1
answer
257
views
Is lead iodide a strong electrolyte?
So, lead iodide is insoluble. I see conflicting answers online. Some say it's a weak electrolyte because it is insoluble, others say it is a strong electrolyte because it is an ionic compound and any ...
- 21
2
votes
1
answer
428
views
Does nitrous oxide decolorize potassium permanganate?
My teacher says that nitrous oxide can't form any complex with manganese in aqueous solution, so it can't be oxidised. However, shouldn't it get oxidised as it is present in the intermediate oxidation ...
4
votes
1
answer
224
views
Do ion-exchange membranes *always* require ions to pass in both directions?
In an answer to this question, it was asserted that:
Student always tend to forget that a solution must remain electrically neutral by all means. If you want a certain ion to leave water, you must ...
- 189
7
votes
1
answer
1k
views
Is there a material that ions can pass through but water can’t?
I was wondering whether there is a material that can pass ions (such as the ions existing in seawater) but not water. I am aware that water molecules are smaller, so they can pass through some ...
- 223
2
votes
0
answers
333
views
Why does copper(II) sulfate solution turn black on addition of excess sodium borohydride?
In my laboratory experiment, I was supposed to reduce copper(II) sulfate to copper by means of $\ce{NaBH4}$, an indication of which was supposed to be a colour change from blue (copper(II) sulfate) to ...
- 219
-3
votes
1
answer
91
views
Determining iron(III) content in mixture of iron(II) and iron(III) [closed]
Problem
Outline a plan of an experiment to determine the percentage of iron present as iron(III) in a solution containing $\ce{Fe^3+(aq)}$ and $\ce{Fe^2+(aq)}$ ions. You are provided with zinc, a ...
- 15
-2
votes
2
answers
732
views
Isolating potassium chloride from sodium chloride and potassium hydroxide
Assume that you have an aqueous solution of sodium chloride and potassium hydroxide. Is it possible to isolate potassium chloride from this?
$$\ce{Na+(aq) + Cl-(aq) + K+(aq) + OH-(aq) -> Na+(aq) + ...
user123142
11
votes
1
answer
620
views
Is there oxygen isotope exchange between dissolved CO2 and H2O?
If you had a sample containing an elevated concentration of $\ce{H2^{18}O}$, and bubbled $\ce{C^{16}O2}$ through it, would some of the oxygen-18 isotope be transferred from water to carbon dioxide?
I ...
- 651
1
vote
3
answers
239
views
Discrepancies in using pOH vs pH to solve H+/OH- concentration change problem
I found an extremely confusing problem in one of the problems we did in class for general chemistry. This was the question:
How many moles of $\ce{H3O+}$ or $\ce{OH-}$ must you add per liter of $\ce{...
- 21
1
vote
1
answer
331
views
Does hypochlorous acid oxidize hydrogen peroxide?
The following reaction is from https://ncert.nic.in/textbook/pdf/kech202.pdf, p. 11:
$$\ce{H2O2 + HOCl -> H3O+ + Cl- + O2}$$
I have to find if $\ce{H2O2}$ is acting like a reducing agent or an ...
- 583
0
votes
1
answer
626
views
Is boiling aqueous solution of copper(II) sulfate safe?
I want to create saturated coper(II) sulfate solution in order to grow crystals. Is boiling a solution of copper sulfate at home safe? Are there any risks? Is the vapour pure water?
- 119
3
votes
1
answer
2k
views
Reaction between concentrated sulfuric acid and sodium bromide
What are the products of the reaction between sodium bromide and concentrated sulfuric acid?
I did the question like this:
$$
\begin{align}
\ce{2Br- &-> Br2 + 2e-} \tag{R1.1} \\
\ce{SO4^2- 4H+ ...
- 27
1
vote
0
answers
52
views
How to calculate pH resulting from dissolving a salt in water? [closed]
The main question is how to calculate the changes in pH after dissolving a salt in water.
Suppose we dissolve 1 gram of magnesium carbonate (MgCO3) in 1 liter of Water. This will result in (...
- 11
0
votes
0
answers
516
views
Nature of Bisphosphonates Binding onto Hydroxyapatite in the Aqueous Phase
In many studies I've read, bisphosphonates (first image) are said to bind remarkably onto bone hydroxyapatite (second image) crystals. It was reported by J. Roelofs et al., (2008) that this mechanism ...
- 467
-4
votes
1
answer
1k
views
Can 5% sulfuric acid and 3% hydrogen peroxide form piranha solution?
I'd like to use 5% sulfuric acid and 3% hydrogen peroxide as an etching solution for copper. (In the past I've used dilute hydrochloric acid and hydrogen peroxide but the generation of chlorine gas ...
- 191
-1
votes
1
answer
955
views
Solubility of nitrogen dioxide in sodium hydroxide
I know $\ce{NaOH}$ can absorb $\ce{NO2}$, but I could not find any data of solubility of $\ce{NO2}$ in $\ce{NaOH}$ at room temperature and atmospheric pressure.
I am trying to figure out how much NaOH ...
- 864
3
votes
1
answer
180
views
Reaction between hydrobromic acid and sodium borate
Write the reaction for a a sodium borate solution being titrated by hydrobromic acid, assuming sodium borate is represented by $\ce{Na3BO3(aq)}$.
I think this is a simple double replacement reaction:
...
- 167
0
votes
2
answers
194
views
What might cause overestimated measured pH value of sodium hydroxide solution pumped with carbon dioxide?
I tried an experiment at home where I had a $\ce{CO2}$ tank pumping $\ce{CO2}$ into a solution of $\pu{28 g}$ sodium hydroxide in $\pu{200 ml}$ water. The initial $\mathrm{pH}$ was $11.24.$
I expected ...
- 59
1
vote
0
answers
798
views
How to prepare a solution of Ferrous Iron?
I need to prepare a solution of Ferrous Iron (Fe2+). This solution will be used to test a water filtration system by simulating the Ferrous Iron that is sometimes present in well water. The system is ...
- 11
0
votes
1
answer
787
views
Why is the enthalpy of solution of hydrated calcium chloride positive?
My book says that the enthalpy of solution of anhydrous calcium chloride is negative because it produces hydrated calcium chloride. But when hydrated calcium chloride is dissolved in water, the ...
- 173
-1
votes
1
answer
151
views
Do coordination complexes with stronger ligands form more stable complexes?
I read that chelate complexes generally are more stable than monodentate complexes. However, I noticed that in the case of $\ce{[Fe(CN)6]^3-}$ and $\ce{[Fe(en)3]^3+}$, this is not observed as the ...
- 173
0
votes
1
answer
119
views
How exactly does a buffer made up of a weak acid and its conjugate base work upon addition of hydroxide ions? [duplicate]
Consider a buffer solution containing a weak acid and its conjugate base ($c_\mathrm{total} = \pu{0.1 mol L-1}$):
$$\ce{HA <=> H^+ + A^-}$$
When $\ce{H+}$ ions are added (from a strong acid), ...
- 551
3
votes
1
answer
2k
views
How to determine the equivalents of OH- in a titration curve
How does one go about determining the equivalents of $\ce{OH-}$ needed for the titration of a weak acid. For example here is the titration curve for Aspartate:
Why is the equivalents for $\mathrm{p}...
- 67
0
votes
0
answers
213
views
Which method has the highest yield of calcium sulfate?
I'm not sure which of following two methods will give better yields for $\ce{CaSO4}$:
A. Add dilute $\ce{HNO3}$ to $\ce{CaCO3}$, followed by dilute $\ce{H2SO4}$; or
B. Titrate aqeuous calcium ...
- 1
-2
votes
1
answer
2k
views
Phenolphthalein + sodium carbonate and phenolphthalein + sodium bicarbonate [closed]
What would the word equations be for the following two situations?
Initially $\ce{Na2CO3}$ and $\ce{NaHCO3}$ were present as 2 unknown powders, dissolved in water, and phenolphthalein was added to ...
6
votes
2
answers
568
views
Balancing reaction between copper and nitric acid given the ratio of formed nitrogen oxides
Problem
$\ce{Cu}$ reacts with $\ce{HNO3}$ according to the equation
$$\ce{Cu + HNO3 -> Cu(NO3)2 + NO + NO2 + H2O}$$
If $\ce{NO}$ and $\ce{NO2}$ are formed in 2:3 ratio, what is coefficient of $\ce{...
- 511