Questions tagged [aqueous-solution]

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

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8 votes
3 answers
10k views

How to set up equation for buffer reaction?

For buffer equations, how can you tell what to react with water? For example, if I have a 1 M acetic acid solution and 1 M sodium acetate solution (a conjugate acid-base pair) mixed together and am ...
27 votes
3 answers
28k views

Why do salts such as NaCl dissolve?

If we look at solubility of salts in water, we are told that they disassociate, because the positive $\ce{Na}$ ion is attracted to the partially negative oxygen in water and the negative $\ce{Cl}$ is ...
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19 votes
3 answers
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Why copper(I) is unstable in aqueous medium?

I am expecting that $\ce{Cu+}$ attains a $\mathrm d^{10}$ configuration by losing one electron from s-subshell. Since it has fully filled d-orbital, it should be stable. But it is found that it is ...
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27 votes
1 answer
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Are all NO3- salts soluble in water? If so, why?

All the examples of $\ce{NO3-}$ salts are soluble in water (all that I know about). Is it always so or there is some salt which doesn't dissolve in water? If so what is the reason behind it?
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12 votes
2 answers
9k views

Should bromine water be called a solution?

Bromine water is a reagent which is used to test for unsaturation in organic compound. It is $2.8~\%$ bromine in water. In many places, it is refer to as bromine solution. But it is observed that ...
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6 votes
3 answers
46k views

Is magnesium sulfate basic, neutral or acidic?

A question in my college test was whether $\ce{MgSO4}$ is neutral, acidic or basic. I was told to solve this kind of problem by hydrolyzing any ions that do not "come from" a strong acid or a strong ...
21 votes
2 answers
4k views

pH probe bulb - what is happening within the glass?

I am trying to understand how the glass bulb of a pH electrode of a pH meter works - the glass bulb itself. Not the reference electrode or the rest of the electrode (HCl, Ag/AgCl wire, etc...), the ...
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1 vote
2 answers
14k views

What determines whether a double displacement reaction will occur?

In normal displacement reactions, reactivity plays a large role and sometimes the reaction doesn't even happen. So is there anything limiting double displacement reactions? For example $\ce{2KI + Pb(...
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4 votes
1 answer
591 views

How can I measure the amount of quinine in a home-made tonic water?

I'm into mixology, and lately I've been looking into experimenting with home-made tonic water, by extracting quinine (quinine salts) from cinchona barks in an acidic aqueous solution. I've read a bit ...
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20 votes
3 answers
55k views

Why there is no change in water level when salt is added?

Let us say we have one glass of water and after that when we add one or two spoon of salt then we notice that salt dissolves in it but when we measure the water level we found that there is no ...
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27 votes
7 answers
20k views

Why is silver chloride less soluble than silver nitrate?

Related: Reaction between silver nitrate and aluminum chloride Experimentally, $\ce{AgCl}$ is insoluble in water, but $\ce{AgNO3}$ is soluble. They're pretty common in a lab (well, $\ce{AgCl}$ is a ...
20 votes
2 answers
1k views

Stability of H⁺ ion

I know that $\ce{H+}$ is not possible in water and it is present as $\ce{H3O+}$. But later on I come to know that even $\ce{H3O+}$ is not possible and that it is present as $\ce{H9O4+}$. Why does this ...
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5 votes
3 answers
12k views

Can there be more solvent in a solute?

Something I know that leads to this question: Water dissolved in ethanol. It might sounds weird to say water as a solute. Textbooks always says that solvent is the one present in larger quantity. ...
4 votes
2 answers
1k views

Basis for the hydrophobic effect?

I'm confused about why hydrophobic molecules, which do not have high polarity, would have a tendency to attract and cluster with themselves. It is easier to understand the hydrophilic as long as one ...
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20 votes
2 answers
26k views

Why does solubility of solids sometimes decrease with temperature increase?

Recently I was researching $\ce{Ca(OH)_2}$, and I found this on Wikipedia: \begin{array}{|c|l|}\hline {\rm \color{blue}{Solubility~in~water}} & {\mathrm{0.189\,g/100\,mL}\ (0\,^\circ\mathrm{...
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9 votes
1 answer
2k views

Vapor pressure of immiscible liquids

I have read that vapour pressure of a mixture of two immiscible liquids is $$P=P^0_A + P^0_B$$ where A and B are immiscible liquids. If they are immiscible, they would form separate layers. Thus ...
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8 votes
2 answers
7k views

Is there a difference in the reactions of a dilute acid and a concentrated acid?

All of the exams that I've sat so far, and the homework questions I've had, always ask for the reaction between a substance and a dilute acid. Is there a difference in the reaction between a dilute ...
6 votes
3 answers
2k views

In my homemade electrolysis setup, only the negative end bubbles?

I've created an electrolysis setup by connecting a $6~\mathrm{V}$ battery to a cup filled with saline water via pencils; I am confused as to why only the negative pencil bubbles though. After running ...
5 votes
1 answer
10k views

How can an insoluble compound be a strong electrolyte

Here's a quote from Petrruci General Chemistry (pg. 160): Silver chloride, $\ce{AgCl}$ is an insoluble ionic compound. When $\ce{AgCl}$ dissolved in water, it is 100% dissociated into $\ce{Ag}^+\text{...
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4 votes
1 answer
306 views

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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5 votes
1 answer
788 views

Formation of MnO2 vs [Mn(H2O)6]4+ in aqueous solution

I am looking for reasons why $\ce{Mn(IV)}$ wouldn't be stable as a hydrate. I know that from standard reduction potentials it exists as a ppt of $\ce{MnO2}$, but what is stopping it from being a ...
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2 votes
2 answers
9k views

Why is potassium phosphate KH2PO4 in this reaction?

This is a continuation of this question because the first thing that came in my mind is that why potassium phosphate in this reaction is $\ce{KH2PO4}$ and not $\ce{K3PO4}$? In the wikipedia article ...
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28 votes
5 answers
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Why is water "the universal" solvent?

This is an old question that our textbook tried to answer but worsened the situation. Many things are soluble in water. So many, that studying solutions will always require studying aqueous ones. It ...
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26 votes
4 answers
3k views

What software can calculate aqueous solution equilibria?

What software is available out there to calculate the equilibrium in a set of reactions in aqueous solution? In particular, I'm interested in software general enough to simulate things like titration ...
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7 votes
1 answer
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Reaction between alumina and aqueous sodium hydroxide, which one's right?

My chemistry textbook has a rather annoying irregularity. It cites two different reactions for the same set of reactants (aluminium oxide, sodium hydroxide and water) without the slightest mention of ...
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23 votes
4 answers
16k views

Can other substances be dissolved in a saturated solution?

If I have a liter of water fully saturated with sucrose would it be possible to dissolve something like salt or any other substance in the water? Or when the solution is saturated, is it impossible to ...
18 votes
4 answers
52k views

How much can the pH change through dilution?

Consider an acidic solution with Hydrogen ion concentration, $\ce{[H+]}$ of $10^{-5}\:\mathrm{M}$. Since $\:\mathrm{pH} = -\log \ce{[H+]}$ the $\:\mathrm{pH}$ of solution is $5$. Suppose we dilute ...
4 votes
1 answer
2k views

How is hydration free energy of a solute measured experimentally?

I am reading a paper (Shirts, M. R.; and Pitera, J. W. and Swope, W. C. and Pande, V. S. J. Chem. Phys. 2003, 119, 5740-5761). Near the beginning of the paper (page 5745), the authors state: ...
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3 votes
1 answer
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Is there a difference between ‘ammonium hydroxide’ and ‘aqueous ammonia’?

Water ($\ce{H2O}$) can be added to ammonia ($\ce{NH3}$) in order to form ammonium hydroxide ($\ce{NH4OH}$): $$\ce{NH3 + H2O -> NH4OH}$$ But we know that ammonia is gaseous at STP so writing $\ce{...
3 votes
1 answer
612 views

Can acid-base reactions occur in a non-aqueous medium?

To better illustrate my question, allow me to refer to the case of ammonium chloride, formed through a classic acid-base reaction. The reaction between ammonia and hydrogen chloride to give ammonium ...
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18 votes
1 answer
2k views

Why does the graph of the electrical conductivity of sulfuric acid/water solutions have this knee in the ~85%-~92% range?

This answer to an earlier question regarding the electrical conductivity of sulfuric acid provides a graph showing the conductivity of sulfuric acid/water mixtures ranging from 0% to 100% sulfuric ...
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11 votes
4 answers
407 views

Is there any electronic component to water conductivity?

Answers to Decrease in temperature of a aqueous salt solution decreases conductivity indicate that the electrical conductivity of salt solutions arises from the mobility of ionic species and therefore ...
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6 votes
1 answer
22k views

How to Convert Sucrose to Glucose and Fructose

If you have some sort of sports drink that contains sucrose, how would you take that sucrose and break it down into its components, glucose and fructose? I know that sucrose + water will break it ...
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5 votes
2 answers
2k views

Calculating approximate pH of polyprotic acids

When I took up ionic equilibria and titrations after a long break, I found it hard to solve the questions regarding pH calculations of polyprotic acds. Consider these two questions as examples:- ...
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3 votes
2 answers
18k views

How does NaCl (or any inorganic salt) increase surface tension?

Does the compound "prefer" to stay in the solution? If yes, wouldn't the surface tension of the solution be equal to that of pure water, since only water is in the surface? See: Does NaCl reduce the ...
2 votes
1 answer
9k views

Reaction of sulfate ion in copper sulfate electrolysis

I am planning to try copper plating a piece of metal by performing electrolysis on an aqueous solution of copper sulfate. I plan run an electrical current with the metal I want to plate as the cathode ...
2 votes
2 answers
11k views

Is H+ (in an aqueous solution) = H3O+? [duplicate]

I was learning about autoionization in science and my science teacher wrote $\ce{H3O+}$ as $\ce{H+}$ — now, my intuition would lead me to assume that: $$\ce{H3O+} = \ce{H+}$$ But, $\ce{H+}$ is just ...
0 votes
1 answer
3k views

What is the colour of chromium(III) chloride solution?

I had a question asking about the colour of the solution of chromium(III) chloride in my exam, all my colleagues have different answers, I couldn't find any exact answer after searching!
9 votes
1 answer
229 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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7 votes
2 answers
427 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{...
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7 votes
2 answers
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Is there a soluble salt, or compound that when dissolved in water results in a solution with density less than pure water?

Generally water soluble salts tend to 'fit between' the molecules of water such that the volume of the resulting solution does not increase much relative to the volume and added mass of the salt. So ...
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6 votes
1 answer
2k views

Can I synthesize iron acetate like this?

The oxidation state of the iron doesn't matter too much; I am just trying to make an attractive red-brown ink. Here are some instructions I prescribed to a friend. Here's an approximately decent ...
6 votes
1 answer
3k views

Saturation of multiple solutes

Can a liquid which is saturated with a single solute, dissolve a different solute, or is saturation a universal thing? I ask because I’ve seen that different solutes have different points (amounts) at ...
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6 votes
2 answers
26k views

Electrolysis of aqueous copper (II) nitrate

There are two copper blocks sitting in the $\ce{Cu(NO3)2 (aq)}$ solution, a battery is attached onto both of them, providing enough energy to start the reaction. Since solid pieces of copper are ...
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5 votes
1 answer
2k views

Why do some solid chemicals dissolve better in colder water?

I just discovered that some solid chemicals, such as $\ce{Na2SO4}$, dissolve better in cold water than hot water from here and would like to know if there is any particular reason as to why. Is it ...
3 votes
2 answers
3k views

Dangers of expired bleach?

I have some unopened Clorox bleach bought over a year ago (at $8.25~\%\ \ce{NaOCl}$) and read on Wikipedia that bleach naturally decomposes according to $$\ce{3 NaOCl (aq) -> NaClO3 (aq) + 2 NaCl(...
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3 votes
2 answers
258 views

How to measure quantities at standard state when this state is a hypothetical one?

Consider the reaction $$\ce{A(g) + H2O(l) <=> B(aq) + C(g)}$$ If all gases and solutions were ideal, the standard state would be pure water, the solute B at a concentration of 1 M, the gases A ...
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2 votes
1 answer
288 views

How to calculate molar concentration from equilibrium equations with no initial concentration given?

I have the equations: \begin{align} \ce{CO2(g) + H2O(l) &<=> H2CO3(aq)} &\quad K_1 &= 10^{-1.47} \tag{1}\\ \ce{H2CO3(aq) &<=> H+(aq) + HCO3-(aq)} &\quad K_2 &= 10^{-...
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1 vote
2 answers
321 views

Does adding solutes to water alter its triple point? [closed]

Does adding solutes to water alter its triple point? If yes, how do we find the new temperature and pressure of this point?
1 vote
2 answers
549 views

Why do increasing concentrations of zinc chloride not linearly decrease the freezing point?

I did an experiment on how different concentrations of $\ce{ZnCl2}$ affect the freezing point of demi water. My results were that till a concentration of about $10\ \mathrm{mol\,dm^{-3}}$ the freezing ...
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