Questions tagged [aqueous-solution]

For questions relating to compounds dissolved in water and resulting reactions and acid-base equilibria.

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0 answers
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Adjusting the Equilibrium of a Solution to change pH by kinetic impact [closed]

I am a physics student with introductory chemistry experience. Im being tasked with using collisions to show the differences in elasticity of collisions (basically how much kinetic energy is lost). I ...
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83 views

Solubility and solubility product in relation to the number of ions in a formula

I was taught that if a salt was formed by ions with higher charges, the lattice energy would be also higher (Born-Landé), and the solubility in water would be lower, as it takes more energy to break ...
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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 ...
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-1 votes
1 answer
81 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 ...
2 votes
2 answers
176 views

Magnesium vs calcium vs barium ions from these 3 tests

How do I pick up the difference between barium, calcium, and magnesium ions? I had to do a quantitative analysis practical exam: I was given an aqueous solution of a salt, and when adding separately ...
2 votes
1 answer
112 views

How does pH affect the rate that CaCO3 dissolves in freshwater?

It is my understanding that calcium carbonate dissolves faster in lower pH environments. I am interested to know how higher PH levels affect the rate of dissolution. So I have broken this question ...
1 vote
2 answers
386 views

What will be the products of the reaction between a metal (i.e. zinc) and a solution containing two dilute acids i.e. HNO3 and H2SO4? [closed]

The metal is dipped into a beaker that has the two acids, sulphuric (VI) acid and nitric (V) acid in equal concentrations. In my preliminary research, I found that there might be several possibilities....
10 votes
3 answers
2k views

Why is there a decrease in the total volume when NaOH dissolves in water?

When a solute is added to a solvent, the volume of the solution should be equal to the sum of the individual volume of the solute and solvent (i.e total volume), right? But why is there a decrease in ...
2 votes
2 answers
86 views

What is the significance of charge balancing when analysing system speciation (carbonate system given as an example)?

Following on from my previous question and accepted answer, How do I quantify the carbonate system and its pH speciation?, I also calculated a charge balance ($CB$) on the system where $z$ is the ...
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0 answers
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Why does the pH of very strong NaOH solutions not make sense? [duplicate]

I'm wondering why the pH of extreme alkaline solutions, such as the case with $\pu{10 M}$ $\ce{NaOH}$ does not make practical sense and I'm wondering why this is the case? Refer to my calculations ...
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7 votes
2 answers
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Why do we call salts such as AgCl sparingly soluble?

Though we use the term practically insoluble for salts like $\ce{AgCl}$ in inorganic chemistry, we preferably call them "sparingly" soluble salts in physical chemistry seeing their tiny ...
1 vote
0 answers
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Solubility comparison for para-nitrophenol and phenol

During lecture with our chemistry teacher, he randomly asked us to compare solubility of phenol and p-nitrophenol, we expected p-nitrophenol to have greater solubility than phenol due to better dipole ...
2 votes
1 answer
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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 ...
0 votes
0 answers
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How to measure pottery glaze leaching?

I am looking for a way to know if glazes from pottery leach chemical compound in water. Those are usually metal ions: cobalt, manganese, chrome, etc. The procedure would be to place hot water in the ...
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4 votes
1 answer
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How do I quantify the carbonate system and its pH speciation?

I did Environmental Water Chemistry as part of my undergraduate course where we quantified pH-speciation for the full carbonate system and I got it right according to my tutor. My speciation profile ...
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2 votes
0 answers
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At constant solvent activity, do solution properties depend on identity of the solute?

When a substance is dissolved or mixed with water in high concentrations, the activity of water drops from 1 to a value that depends on the substance and its concentration. Is it correct to say that ...
1 vote
0 answers
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How the optical fibre pH microsensors work?

Just browsed through the chemical sensor products of the company, called PreSens (https://www.presens.de/products/ph/sensors) in order to look for a precise method to measure pH change in a ...
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0 votes
1 answer
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amorphous silica (diatomaceous earth) dissolution and precipitation using household bleach or ammonia [closed]

I'm a layman not a chemist. My question is whether it's possible to dissolve amorphous silica in room temperature water mixed with a commonly available alkaline household product and then have it ...
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0 votes
2 answers
224 views

Electrical conductivity of a NaOH solution

We are doing a simple water electrolysis experiment but I have issues with the electrolyte solution. Took 450ml of distilled water and slowly dissolved 50g of NaOH until heating ceased. If I'm not ...
-5 votes
1 answer
57 views

Hydrofluoric acid

At work we have a large tank that is comprised mostly of hydrofluoric acid, I don't know the dilution factor as I'm not the one making the bath, but I have a question, when emptying the bath we tried ...
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4 votes
1 answer
196 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 ...
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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 ...
3 votes
1 answer
87 views

Variation of conductance of saturated aqueous solution with temperature

The following question was asked in JEE Mains 2020: Let $C_{\ce{NaCl}}$ and $C_{\ce{BaSO4}}$ be the conductances (in S) measured for saturated aqueous solutions of $\ce{NaCl}$ and $\ce{BaSO4}$, ...
2 votes
0 answers
44 views

Gouy-Chapman model

Recently I have been investigating the problem of a neutral solutions (with equal number of anions and cations) interacting with an infinite surface $z=0$ with electrostatic potential $\phi(z=0)=\...
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2 votes
0 answers
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Transforming hydroxyl group to carboxylic acid in an aqueous environment

I am looking for a way of converting a hydroxyl group into a carboxyl group in an aqueous environment for eventual coupling to an amine. There seem to be plenty of ways of achieving this in various ...
9 votes
1 answer
224 views

Details of what actually happens in cold sulfuric acid between 80 and 90%; what molecular changes cause the viscosity to skyrocket?

AChem's answer to Why does the graph of the electrical conductivity of sulfuric acid/water solutions have this knee in the ~85%-~92% range? includes this plot from Horace E. Darling in "...
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3 votes
2 answers
174 views

Why is my battery of galvanic cells not enough to power a lamp rated for a lower voltage than the battery provides?

I made a series of 12 galvanic cells with saltwater as an electrolyte and zinc and copper as electrodes. It produces 8.8 V, but it can't even light a 2.5 V bulb (the bulb can be lit by a 1.5 V source)....
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0 votes
1 answer
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Purifying ferrous sulfate

For my wood staining experiments I have purchased 1 kilo of ferrous sulphate as a source of iron(II). It turned to be quite oxidised (yellowish) and the its solution is muddy yellow instead of green. ...
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0 answers
53 views

How to find pH for acetate buffer?

Calculate the pH of the solution that results when $\pu{40.0 mL}$ of $\pu{0.100 M}$ $\ce{CH3COOH}$ is mixed with $\pu{30.0 mL}$ of $\pu{0.200 M}$ $\ce{NaCH3COO}.$ $K_\mathrm{a}(\ce{CH3COOH}) = \pu{1....
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1 vote
1 answer
138 views

How does CO2 'dissolve' in water (or blood)?

I'm trying to understand CO2 dissolved in blood, carbonic acid and the bicarbonate ion. I think of 'dissolving' as in NaCl dissociating into Na+ and Cl- ions sloshing around in water. CO2 isn't ...
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0 answers
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Misconception regarding mean ionic activity coefficient and applying it to equilibrium constants

I probably have some simple misconception about the mean ionic activity. The mean ionic activity coefficient is defined as $$ \gamma_{\pm} = \sqrt[^{p+q}]{\gamma^p_+\gamma^q_-} \tag{1} $$ I'm just not ...
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2 votes
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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 ...
-3 votes
1 answer
59 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 ...
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-4 votes
2 answers
61 views

What happens during a displacement reaction? [closed]

When Zn metal is added to a solution of Cu(II)SO4, Zinc displaces Cu to form ZnSO4 as Zn is more reactive than Cu. What I don't understand is how. 1- What I'm assuming is: Zn metal collides with [SO4]...
0 votes
0 answers
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How to remove oil/grease contaminant from an aqueous solution?

I have a solution of water and calcium nitrate that is contaminated with some sort of heavy petroleum oil, semi-solid at room temperature a bit like petroleum jelly, and a strong odor of very crude ...
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-2 votes
2 answers
146 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? I'm thinking about the following: Na+(aq) + Cl-(aq) + K+(aq)...
1 vote
1 answer
45 views

How to find ion concentrations at various points in a solution that will precipitate multiple insoluble salts?

The solubility product constant of lead (II) iodide is $1.2 \times 10^{-5}$ at 273 K. The solubility product constant for lead (II) carbonate is $1.5 \times 10^{-13}$ at the same temperature. 50 ...
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11 votes
1 answer
546 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 ...
1 vote
3 answers
97 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{...
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1 vote
0 answers
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What is the resulting solution after leaching hardwood ash with water?

After doing online research, I've noticed there are differing interpretations on what happens when ash is mixed with water, so I've come here seeking clarification on what indeed happens, and also ...
1 vote
1 answer
111 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 ...
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1 vote
1 answer
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What is the effect of adding another solute to the solubility of the initial solute?

Let's say we have a saturated salt solution with 35 g/100 mL NaCl in water. If we add another solute up to its saturation concentration, for example 182 g/100 ml sucrose (C12H22O11), what happens? ...
-1 votes
1 answer
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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?
1 vote
1 answer
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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+ ...
0 votes
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I spilled some .1M Copper Sulfate on my sweater [duplicate]

I have accidentally spilled some .1M solution of Copper Sulfate (CuSO4) on my white cotton sweater. It left a light blue stain and I’m wondering how I might successfully remove the stain from the ...
0 votes
0 answers
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Adequate emulsifier for dimethoate

Dimethoate is a broad-spectrum systemic insecticide and miticide. It is sold for example as Drexel in the US or as Danadim in Australia (there are many others, Rogor, etc). The formulation from Sico ...
1 vote
0 answers
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Chemical Equilibrium of the Esterification Reaction Between Propanol and Ethanoic Acid

I am trying to investigate the relationship between temperature and equilibrium constant of the esterification reaction between propanol and ethanoic acid in reflux system, with conc. sulphuric acid ...
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0 answers
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Why ppm500 water TDS scale is used and how accurate it is?

So, most TDS meters, it seems, uses this scale. To qoute: The conversion from EC to ppm is as follows: ppm500 = EC x 500 ppm700 = EC x 700 Some examples of how ...
0 votes
0 answers
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Which single parameter can tell about the absolute as well as relative position of a solvent wrt a specific polymer in Hansen Space?

I am trying to represent solutions of a specific polymer (let's say PVDF) dissolved in various solvents using a single parameter. By various solvents I mean single solvent (e.g. DMF) or solvent blends ...
0 votes
0 answers
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Selective Removal of Sodium Acetate

I am currently working on an extraction and synthesis of sodium salicyate from acetylsalicylic acid and sodium hydroxide. After doing a liquid-liquid extraction from DCM, using a sodium hydroxide ...

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