Questions tagged [solutions]

This tag should be applied to questions dealing with solutions of any kind. A solution is a liquid or solid phase containing more than one substance where, for convenience, one (or more) substance(s) called the solvent is treated differently from the other substances, which are called solutes. If water is the solvent, then the more appropriate 'aqueous-solution' tag should (also) be specified.

Filter by
Sorted by
Tagged with
50 votes
9 answers
515k views

Why does ice water get colder when salt is added?

It is well known that when you add salt to ice, the ice not only melts but will actually get colder. From chemistry books, I've learned that salt will lower the freezing point of water. But I’m a ...
cspirou's user avatar
  • 617
29 votes
3 answers
88k views

Is alcohol really a solution?

A friend recently sent me the following chemistry joke: As a lover of puns, I'd like to enjoy it, but I think that it is actually false the way it is phrased. A solution is defined as: "a ...
JessieArr's user avatar
  • 409
29 votes
3 answers
29k 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 ...
Gerard's user avatar
  • 3,433
28 votes
5 answers
17k views

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 ...
M.A.R.'s user avatar
  • 10.6k
25 votes
4 answers
30k views

How does oil on the surface of water prevent rust?

I distinctly remember a side-by-side comparison from a book where there are two nails submerged in water, in two beakers: one nail had a layer of oil on top of the water, and that nail didn't rust; ...
Zubo's user avatar
  • 1,210
23 votes
4 answers
18k 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 ...
Samantha Clark's user avatar
23 votes
5 answers
6k views

Can gases be "immiscible"?

Anyone know of any examples of gas mixtures that phase separate, analogously to the way immiscible liquids do? They would have to be extremely non-ideal. I might guess one might have to be much ...
ericksonla's user avatar
  • 1,690
22 votes
4 answers
5k views

A drop of water in a tin of sugar: Which one's the solvent, the sugar or the water?

The other day, when we were dealing with the chapter Solutions, our teacher asked us this: If I add a drop of water, to a tin full of sugar (without mixing it in), what's the solvent here? The ...
paracetamol's user avatar
  • 18.7k
21 votes
3 answers
5k views

Does freezing a solution with water always cause the water to separate and form the ice lattice?

I'm curious, I was trying to look into the affect of freezing a solution with water even when the solution is completely miscible. I came across something that detailed this regarding salt water and ...
Jimmy Hoffa's user avatar
21 votes
1 answer
2k views

How to think of solvated electrons?

This excellent answer explains at length what's happening in this fascinating video entitled Liquid Electrons - Periodic Table of Videos. In the screenshot below, the metallic-looking solvated ...
uhoh's user avatar
  • 5,702
21 votes
1 answer
1k views

Is it possible for a compound to be soluble in a mixture of solvents but not the individual solvents?

Some weeks ago one of my friend needed to use turpentine. As a good but ignorant chemist on that point I did some research about it. I found (at the beginning) in the French wikipedia page of ...
ParaH2's user avatar
  • 4,177
20 votes
2 answers
2k views

Can a stoichiometric mixture of oxygen and methane exist as a liquid at standard pressure and some (low) temperature?

This answer to the question Pre-mixing cryogenic fuels and using only one fuel tank written by a non-chemist (me) begins with: At STP: LOX's boiling point is 90.19 K Methane's freezing point is 90....
uhoh's user avatar
  • 5,702
20 votes
2 answers
13k views

What causes the lowering of vapour pressure in volatile/nonvolatile solvent mixtures?

"Based on Figure 13.18, you might think that the reason volatile solvent molecules in a solution are less likely to escape to the gas phase, compared to the pure solvent, is that the solute molecules ...
Leponzo's user avatar
  • 409
19 votes
3 answers
59k 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 ...
Shashank's user avatar
  • 1,501
19 votes
2 answers
30k views

How does volume contraction in solvent mixing work?

I recall seeing chemistry demonstrations where a significant amount of a solute is dissolved in a solvent and the solution volume barely changes. Questions regarding this: 1) How is this possible? 2)...
docscience's user avatar
  • 2,753
17 votes
2 answers
15k views

What is the reason for the blue color of an ammoniated electron?

I am quoting a line from a book regarding reactivity of alkali metals with liquid ammonia. The blue colour of the solution is due to the ammoniated electron which absorbs energy in the visible region ...
aman's user avatar
  • 391
16 votes
1 answer
1k views

What is happening in this video of solvated electrons donated from sodium in ammonia?

I just saw the Periodic Video Liquid Electrons - Periodic Table of Videos where sodium is added to liquid ammonia. The demonstration shows that even if electrons are solvated, if you have a high ...
uhoh's user avatar
  • 5,702
16 votes
2 answers
25k views

Why does like dissolve like?

Polar solvents love polar solutes to be dissolved in it and non polar with non polar. Often said as like dissolves like. Okay, polar loving polar can be understood with help of the facts: same polar ...
Pranjal Rana's user avatar
15 votes
2 answers
7k views

Justification for Freezing Point Depression & Boiling Point Elevation in Solutions?

I was wondering if the following justification for freezing point depression and boiling point elevation are conceptually correct. The reason why I ask this question is because I have been self ...
Tyreke Davis's user avatar
14 votes
3 answers
29k views

Are all homogeneous mixtures just solutions?

Or can there be a homogeneous mixture that is not a solution?
la.vie.en.rose's user avatar
14 votes
3 answers
2k views

Why stepwise dissociation for acids but not hydroxide bases?

My son asked this over the weekend and I didn't have a good answer: how come with polyprotic acids we assume that the release of each $\ce{H+}$ is progressively harder, but with bases like $\ce{Ca(OH)...
HappyHuman's user avatar
14 votes
3 answers
34k views

Why iron reacts differently with concentrated and dilute sulfuric acid?

When $\ce{H2SO4}$ is dilute, $ \ce{Fe +H2SO4 -> FeSO4 + H2} $ and when $\ce{H2SO4}$ is concentrated, $\ce{3Fe +8H2SO4 -> FeSO4 + Fe2(SO4)3 + 4SO2 +8H2O}$ What made the reaction with ...
Ahmed Fwela's user avatar
14 votes
4 answers
33k views

When I dissolve sugar in my cup of tea/coffee, does it become a liquid?

When I dissolve sugar in my cup of tea/coffee, does the sugar go from being a solid to being a liquid? Related: https://physics.stackexchange.com/questions/5562/what-keeps-the-sugar-suspended-in-the-...
User 17670's user avatar
14 votes
1 answer
493 views

Why do some solutions eventually stop boiling and start "popping" as they get more concentrated?

A very long time ago I performed an experiment in my kitchen, part of which was to remove all water from a solution. Unfortunately I don't remember what was in it, but the point is that as the ...
Roman Starkov's user avatar
13 votes
2 answers
10k 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 ...
Nilay Ghosh's user avatar
  • 25.3k
13 votes
1 answer
2k views

Is there a name for this algorithm to calculate the concentration of a mixture of two solutions containing the same solute?

There is an algorithm called "Mischungskreuz" (German for "x of mixing") that is sometimes taught as a shortcut to figure out the following problem: You have two solutions that ...
Karsten's user avatar
  • 39.7k
13 votes
2 answers
646 views

Do azeotropic mixtures evaporate proportionally?

Do azeotropes evaporate, without boiling, in proportionate amounts, or does this property describe their behaviour only at boiling point? Concretely, if 91% isopropyl alcohol/water (by volume, i.e. an ...
OJFord's user avatar
  • 241
12 votes
3 answers
38k views

Differentiation between zinc, aluminium, and magnesium ions in solution

If I have three aqueous ionic solutions in which I know that the cation is $\ce{Al^3+}$, $\ce{Mg^2+}$, or $\ce{Zn^2+}$, how do I find out which is which? I was thinking to add $\ce{OH-}$ in the form ...
dma1324's user avatar
  • 223
12 votes
2 answers
12k views

Why does shampoo lather much more the second time it is applied?

When I shampoo my dirty hair, the first time it does not lather very much. The second time it lathers a lot. Why is this?
trmdttr's user avatar
  • 173
12 votes
3 answers
41k views

How is dissolving a physical change and not a chemical change?

When salt dissolves in water it dissociates and it is no longer in a lattice structure. The electrostatic forces are no longer there and are replaced by water-ion interactions. To me that sounds like ...
la.vie.en.rose's user avatar
12 votes
5 answers
41k views

Is it possible to separate/remove sugar from common drinks, such as juice?

Is it possible to remove sugar from a drink (for example, juice) using common household equipment?
R S's user avatar
  • 315
12 votes
1 answer
4k views

Why is DMSO more polar than other solvents, yet it dissolves ionic compounds worse?

I'm working right now in the solvent importance in ionic character, and I noticed how a binary salt ($\ce{CuCl2}$) dissolved better in methanol than in dimethylsulfoxide, and in contrast, a ...
Farad's user avatar
  • 186
12 votes
4 answers
9k views

Why do solutions become saturated?

Why can a solvent dissolve only a particular amount of solute? If we add more solute to the solution, the number of solute particles in contact with water increases. So rate of dissolution should ...
nilanjana's user avatar
  • 863
11 votes
1 answer
7k views

Why does concentration of solutions of alkali metals in liquid ammonia change the magnetic properties?

In "NCERT Chemistry for Class XI - Volume II", in chapter "s-block elements", under the topic "Chemical Properties of alkali metals", it is given: (vi) Solutions in ...
Vishnu's user avatar
  • 2,040
11 votes
1 answer
64k views

Does concentration of salt increase or decrease rate of rusting?

I want to know whether increasing the concentration of salt, specifically $\ce{NaCl}$, increases or decreases the rate of rusting. There are conflicting theories that explain opposite outcomes: ...
Tejas Ramdas's user avatar
11 votes
1 answer
1k views

Cold-sensitive magic pen

Yesterday, I bought some "magic" rollerball pens (those with water-based ink), available in red, blue and black. They look and write like a normal pen, but have an eraser at the upper end, just like ...
sweber's user avatar
  • 263
11 votes
2 answers
5k views

Why and how are azeotropes formed?

Why and how are azeotropes formed? I could not find a detailed explanation of how azeotropic mixtures are formed anywhere on the internet. Now, that I figured it out myself, I thought I'd share it.
Arishta's user avatar
  • 4,127
11 votes
2 answers
191 views

Peak in beer freezing temperature plot

I left an open beer in the freezer while monitoring its temperature. The first minutes works as expected. But after the plateau, at about −8 °C, a peak appeared: I thought it was an artefact because ...
EyC's user avatar
  • 181
10 votes
4 answers
2k views

Ionic compound having highest solubility in water

Which ionic compound has highest solubility in water? I can find CsBr having highest solubility with 1230 g/L at 25 °C. Note: compounds like ethanol are soluble to any extent in water, but they are ...
Harsh jain's user avatar
  • 1,693
10 votes
4 answers
8k views

Can a solvent be a solid?

Can a solvent be a solid? I do not think so. But is it possible for a solvent to be a solid?
Habib's user avatar
  • 795
10 votes
2 answers
8k views

Are all solutions of weak acid/bases buffers?

I am having a difficult time understanding what makes a buffer a buffer. Buffers in my textbook are defined as a solution of a weak acid or base and their conjugate acid/base. So if I were to just ...
Blakeasd's user avatar
  • 349
10 votes
2 answers
3k views

Limitations of Henry's law

Consider the diagram Henry's law is a gas law that states that the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid. The proportionality factor is called ...
Michael Faraday's user avatar
10 votes
2 answers
1k views

Can aluminium form blue-colored solution in liquid ammonia?

I've read that group 1 elements and group 2 elements with exception of Be form blue-colored solutions in liquid ammonia (Mg requires an electrolytic process). What are the conditions for a metal to ...
Adithya's user avatar
  • 1,401
10 votes
2 answers
2k views

Can I pour a solution into another vessel with no air bubbles?

I have been trying to create a method to create a homogeneous agar solution. What are appropriate techniques to ensure homogeneous solidification of an agar-based aqueous solution? The new solution ...
James Blackwell's user avatar
10 votes
1 answer
20k views

Why do some substances ionize instead of dissolving in water?

My question can also be understood as what make something electrolyte or nonelectrolyte? I think this question stems mainly from my confusion with the definitions of ionizing and dissolving. ...
most venerable sir's user avatar
10 votes
1 answer
11k views

Difference between ideal & ideal-dilute solution

These two terms has been frequently used in Physical Chemistry by Atkins. He describes Raoult's Law using ideal solution while Henry's law using ideal-dilute solution. I thought, at first they were ...
user avatar
10 votes
2 answers
1k views

Apparent contradiction in the type of deviation of an ethanol-water mixture

For a mixture of $\ce{EtOH}$ and $\ce{H2O}$: $\Delta H_{\text{mix}} < 0$ (exothermic) and $\Delta V_{\text{mix}} < 0$ (volume contraction). This means that the unlike interactions are stronger ...
Renganathan Subramanian's user avatar
10 votes
2 answers
3k views

Solubility of gold salt solution?

I was wondering what salts of gold are soluble and which are insoluble. From what I understand, silver is soluble as silver nitrate but insoluble as most other common salts like chlorides and ...
Meep's user avatar
  • 1,687
9 votes
3 answers
3k 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 ...
Yitian Chen's user avatar
9 votes
1 answer
1k views

Can sugars dissolve in liquid ammonia?

Can monosaccharides and disaccharides dissolve in liquid ammonia due to hydrogen bond formation? My rationale is that these sugars may be able to form hydrogen bond with ammonia ($\ce{NH3}$).
Soduthanthanakka's user avatar

1
2 3 4 5
21