What is Aqueous: Definition and 59 Discussions

An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be represented as Na+(aq) + Cl−(aq). The word aqueous (which comes from aqua) means pertaining to, related to, similar to, or dissolved in, water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Aqueous solution is water with a pH of 7.0 where the hydrogen ions (H+) and hydroxide ions (OH−) are in Arrhenius balance (10−7).
A non-aqueous solution is a solution in which the solvent is a liquid, but is not water. (See also Solvent and Inorganic nonaqueous solvent.)
Substances that are hydrophobic ('water-fearing') do not dissolve well in water, whereas those that are hydrophilic ('water-friendly') do. An example of a hydrophilic substance is sodium chloride. Acids and bases are aqueous solutions, as part of their Arrhenius definitions.
The ability of a substance to dissolve in water is determined by whether the substance can match or exceed the strong attractive forces that water molecules generate between themselves. If the substance lacks the ability to dissolve in water, the molecules form a precipitate.
Reactions in aqueous solutions are usually metathesis reactions. Metathesis reactions are another term for double-displacement; that is, when a cation displaces to form an ionic bond with the other anion. The cation bonded with the latter anion will dissociate and bond with the other anion.
Aqueous solutions that conduct electric current efficiently contain strong electrolytes, while ones that conduct poorly are considered to have weak electrolytes. Those strong electrolytes are substances that are completely ionized in water, whereas the weak electrolytes exhibit only a small degree of ionization in water.
Nonelectrolytes are substances that dissolve in water yet maintain their molecular integrity (do not dissociate into ions). Examples include sugar, urea, glycerol, and methylsulfonylmethane (MSM).
When writing the equations of aqueous reactions, it is essential to determine the precipitate. To determine the precipitate, one must consult a chart of solubility. Soluble compounds are aqueous, while insoluble compounds are the precipitate. There may not always be a precipitate.
When performing calculations regarding the reacting of one or more aqueous solutions, in general one must know the concentration, or molarity, of the aqueous solutions. Solution concentration is given in terms of the form of the solute prior to it dissolving.
Aqueous solutions may contain, especially in the alkaline zone or subjected to radiolysis, hydrated atomic hydrogen and hydrated electrons.

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  1. Frankenstein19

    Using 18% by weight ammonium hydroxide to make 16ppm aqueous solution

    TL;DR Summary: Used M1V1=M2V2 but am unsure if formula applies I feel like I could use M1V1=M2V2 but the 18% by weight ammonium hydroxide is confusing me so much. Density of ammonium hydroxide 18% is 0.926 g/cm3 18%V1=16mg/L*200L (18mg ammonium/100 mg of total solution) * V1 = 3,200mg...
  2. Z

    Aqueous solution of tolyltriazole

    How can i make an Aqueous solution of tolyltriazole? i need to make an Aqueous solution of tolyltriazole, but its solubility in water i very low. It dissolves with increasing temperature (50(c)) and redeposits with decreasing temperature. Some sodium hydroxide was added to the solution to...
  3. J

    Which of the following aqueous solutions would test closet to pH 7

    Homework Statement >Which of the following aqueous solutions would test closet to 7 on the pH scale? $a) NaCl$, $b) Na_2CO_3$, $c) NaH_2PO_4$, $d) NaCN$ Homework EquationsThe Attempt at a Solution I don't understand this. So I tried writing chemical equations like for a), NaCl + H20 --> NaOH +...
  4. Irl495

    Rotating magnetic field effect on aqueous mixing (opinions?)

    This is question that can't really get a precise answer without significant modeling or experimentation, but I'm wondering what folks' intuition might be on an answer to the following setup + question: Suppose there is a steel tank made of steel pipe with walls about 0.25 cm thick, internal...
  5. N

    Aqueous Solution vs Liquid Solution

    What is the difference between aqueous solution and liquid solution? Note:I am a high school student and English is my second language. Thanks in advance!
  6. S

    Freezing point of an aqueous solution

    hi i am trying to figure out the way to calculate the freezing point of an aqueous solution which have 5 different components. if someone can refer me to an example or give me and example it will be great thanks in advance sharon
  7. neilparker62

    B Equation for Conductivity of Aqueous Solutions

    I have found a lot of data and graphs showing conductivity (micro-mhos) vs % by weight of various salt solutions. The salts for which graphs appear particularly linear are those of alkali Earth metals - eg sodium, potassium - KI, KBr, KCl etc. Is there a theoretical equation for conductivity vs...
  8. A

    Idea for Aqueous Homogeneous Reactor

    How would a super-critical heavy water cooled and moderated two fluid aqueous homogeneous reactor with nitrate fuel work? Silicon carbide or alumina can be used as cladding for the internal seed core and blanket walls, with the silicon carbide on the blanket wall cladding stainless steel and...
  9. Tam Le

    Aqueous NaCl (aq) & Liquid vs. Aqueous States

    What are we referring to when we denote, say, NaCl (aq)? Are we referring to the dissolved NaCl (Na+ and Cl-)? Are we speaking of the solution as a whole (the dissolved NaCl and water)? Also, how does the liquid state differ from an aqueous?
  10. E

    Life expectancy of Aqueous Flux going LowZ

    Looking for any life expectancy data for water soluble flux going low Z. How long it takes for conductive material to migrate and cause low impedance bridges at any humidity or temperature.
  11. S

    Aqueous Equilibrium: Ka of an Unknown Acid via Titration

    Homework Statement We're given an unknown acid, and dissolve an unknown mass of the acid in an unknown amount of water. We then titrated the solution with an unknown molarity solution of NaOH. After titrating in 10.0 mL of NaOH, we measure a pH of 5. After 34.68 mL of NaOH, we realize we...
  12. E

    Can Ammonium Bicarbonate 'salt out' ethanol alcohol?

    I'm testing Ammonium Bicarbonate in a fermentation process. Is it possible for Ammonium Bicarbonate to 'salt out' Ethanol? Compounds such as Sodium Carbonate and Ammonium Sulfate are able to salt out ethanol.
  13. phoenixXL

    Aqueous Tension(Gaseous State)

    Question In a container of capacity 1-Litre, air and some liquid water is present in equilibrium at total pressure of 200 mm of Hg. This container is connected to another 1-Litre evacuated container. Find total pressure inside the container when equilibrium is again stabilized. Aqueous Tension...
  14. E

    Will (NH4)HCO3 Form in Polar Solvents?

    I know aqueous Ammonium Bicarbonate forms when NH4+ and HCO3- ions are present in water after they've dissolved from their gaseous states of NH3(g) and CO2(g). This occurs in the reaction: NH3(g) + H2O(l) + CO2(g) => (NH4)HCO3(aq) If Ammonia gas and CO2 are present above a polar organic...
  15. P

    Electrolysis of Aqueous Sodium Iodide

    According to my chemistry textbook, the I- ion is discharged at the anode. Yet, according to standard electrode potential values, the OH- ion should be discharged at the anode. Thoughts on this please?
  16. M

    Is Delta H of formation the same for NH4NO3 Aqueous and in Solid Form?

    I am doing a project in Chemistry and I need to use Hess' Law to cancel two equations and if in one equation the NH4NO3 is solid and in the second one the NH4NO3 is aqueous. The equations are: 1: NH4NO3 (s) + HCl (aq) --> HNO3 (aq) + NH4Cl (aq) 2: NH4OH (s) + HNO3 (aq) --> H2O (l) + NH4NO3...
  17. U

    How does an ion in aqueous soln induce the same charge on a membrane?

    So if we have an ion, say Cl- in solution, and we have a membrane immersed into the solution. Apparently there is a method in which any ion, of any charge is inhibited from crossing the membrane because it induces the same charge as itself on the membrane. This is called dielectric...
  18. T

    Electrolysis of dilute aqueous solutions

    Homework Statement If dilute, aqueous magnesium bromide is electrolyzed, one product is formed at each electrode. Identify the product, state the electrode it occurs at (anode or cathode) and state a reason for your choice of product. Homework Equations Mg2+(aq) + 2e- --> Mg(s) E°red = -2.37 V...
  19. V

    Identifying Undissolved Silver Halides in Precipitation Reactions

    Homework Statement A sample of an aqueous solution of sodium halides is added to a sample of an aqueous solution of silver nitrate, resulting in a precipitation. To the mixture containing the precipitation was added a sample of an aqueous solution with ammonium hydroxide, dissolving the...
  20. D

    Puzzled by aqueous solution terminology

    I'm just beginning to learn general chemistry, and I'm reading my textbook's chapter on aqueous solutions. My question is, why do we term a solution of an ionic compound (like NaCl) like this: NaCl(aq) instead of: Na+(aq) + Cl-(aq) ? Technically, when the sodium chloride is...
  21. S

    Aqueous equilibria, buffered solutions

    I have two problems. Homework Statement How many moles of Na2CO3 must be dissolved in 250 mL of 0,125 M NaHCO3 so that the solution has a pH of 10,00? Homework Equations The powers of the concentrations are the coefficients in the chemical equation. The products of the...
  22. J

    What does aqueous workup mean?

    What does "aqueous workup" mean? I'm taking a second year organic chemistry and it's a slightly advanced level but I didn't take the 1st year advanced level org.chem. so I may have missed a couple of common terms. What I don't understand is what does workup mean? At the end of some reaction...
  23. T

    Determine the equilibrium pH of aqueous solutions for the following strong acids

    Determine the equilibrium pH of aqueous solutions for the following strong acids or bases: (a) 257mg/L of HSO4- ; (b) 10nM NaOH ; (c) 75ug/L of HNO3
  24. T

    How to eliminate mold in aqueous solution

    Ok, So I am a junior chemistry major doing organic research, but my question hasn't really occurred in organic lab and is really more microbiology related, but I assume chemists in certain fields have either run across this problem or already know how to prevent this from happening. I have a...
  25. M

    Oxoacid strengths in aqueous solutions

    Hey there, My textbook doesn't expand on this much and I'm unsure if I'm just not seeing some obvious connection; I'd appreciate it if someone could clarify this for me. I'm studying the Bronsted-Lowry theory and the strength of binary and ternary acids. I understand how, for example, H2SO4...
  26. C

    Q : write products formed when polyester is heated with aqueous sodium

    Q : write products formed when polyester is heated with aqueous sodium hydroxide I know is hydrolysis , and the product will be alcohol and carboxylic acid ... but will the -OH in carboxylic acid replaces with -ONa or not ?? It say heated with , but doesn't mean react .. so does heated...
  27. M

    Writing Chemical Equations, Is It a Gas or Aqueous Solution?

    Hello, I understand that this question may seem rather obvious for some. Nonetheless, it is something that seems to have thrown me off a number of times. When writing chemical equations involving acidic or basic solutions, I know that the acid on the reactant side is written with the state...
  28. H

    Aqueous systems questions

    I had these two questions in a test and I was completely stumped. 1. Make a 1-2L buffer solution containing methanoic acid and methanoate ions and with a pH of 3.74 using 1.07molL-1 HCOOH, solid HCOONa, 1.04molL-1 HCl, 1.16molL-1 NaOH(not all together). pKa(HCOOH)=3.74 M(HCOONa)=68gmol-1...
  29. R

    Why can't hexane or toluene solutions dissolve in aqueous bromine?

    I have just carried out a lab experiment today and desperately need some help! 1. The Experiment: In my experiement I attempted to mix a solution of hexane with aqueous bromine. I started off by adding 15 drops of bromine into a test tube and then added 7 drops of hexane ontop of that...
  30. U

    Acid-Base Chemistry in Aqueous Solutions

    Homework Statement What are the final hydrogen ion concentration and pH of of a solution obtained by mixing 400 mL of 0.2 M NaOH with 150 mL of 0.1 M H3PO4? pKa's are 2.12, 7.21, 12.32 Homework Equations Henderson-Hasselbach: pH = pKa + log [b]/[a] The Attempt at a Solution 0.2 M...
  31. F

    Troubleshooting Evaporation with a Rotary Evaporator

    Hy ! I have a problem and I need ur help.I tried to evaporate the water from a solution using the rotary evaporator but it didnt work.I don't know what i did wrong.Maybe u can help me or tell me which other method can I use? Thank u Greetings
  32. F

    Why can't alcohol react with aqueous NaOH?

    Hi, alcohol is able to react with Na (s), but not NaOH (aq) Why is it so? In aqueous NaOH, there are mobile Na+ and OH-, so shouldn't alcohol be able to react with Na+ to form salt too? Many thanks!
  33. H

    Solubility Constant vs Aqueous solubility

    Homework Statement The solubility constant for AgBr in water is 5.2 x 10-13. What is the aqueous solubility of AgBr? Homework Equations Ksp= [Ag+][Br-] AgBr is a constant and therefore is not part of the Ksp.The Attempt at a Solution NVM solved problem. Should use ICE table.
  34. T

    Calculating Mass Extracted from Aqueous Solution X

    Homework Statement When 200 cm^3 of an aqueous solution X with concentration 10.0 g/dm^3 was shaken with 100cm^3 of solvent 1-pentanol , 1.60 g of X was extracted . If the aqueous solution was once again shaken with 100 cm^3 of 1-pentanol after the first extraction , what is the mass of X...
  35. S

    Are ions always aqueous inside the cell? (simple question)

    Hello guys, So there are hydrogen ions inside the cell which is pumped out in cellular respiration. Now my question is when they say hydrogen ions are inside the cell are these actually dissolved in water, ions can not exist without being dissolved right, why is that they are so reactive...
  36. M

    Determining the Mass percent comp. of an Aqueous Hydrogen peroxide

    Homework Statement In lab we recorded a barometric pressure of 768.2 torr. Suppose we didn't have access to a barometer and assumed that atmospheric pressure was 760 mm Hg. Would the mass percent of hydrogen peroxide that you calculated for the solution be higher or lower than the value you...
  37. F

    Solved: Calculate pH of Aqueous Solution w/ HBr(g)

    [Solved] pH of Aqueous Solution Homework Statement Calculate the pH of the following aqueous solution prepared by adding 3.0L HBr(g), measured at 27 degrees Celsius, 757 mmHg pressure, to sufficient water to give 0.10L of solution. Homework Equations pH = -log[H+] The Attempt at a...
  38. S

    Calculate the [H3O+] concentration (in M) in a 0.1 M aqueous solution of NH3

    Homework Statement Calculate the [H3O+] concentration (in M) in a 0.1 M aqueous solution of NH3. [Kb = 1.8 x 10–5 ] (a) 7.5 x 10–12 M (c) 1.8 x 10–6 M (b) 3.0 x 10–10 M (d) 1.3 x 10–3 M Homework Equations ΔTb = Kb x m The Attempt at a Solution So... I'm kind of at a loss here...
  39. G

    Solving pH of an Aqueous Solution of Weak Acid HCOOH

    Homework Statement hey guys, I've got a prob, i kinda know how to do this question but i can't get past the first step. i want to write an equilbrium expression by I am not sure what the chemical reaction is. any help would be good Homework Equations A solution of a weak acid, HCOOH...
  40. L

    Aqueous and gaseous elements and compounds?

    Homework Statement Predict the sign of ΔS(sys) for each of the following processes: a) Zn(s)+2HCl(aq)-->H2(g)+ZnCl2(aq) b) CH3CH2CH3(g)+5O2(g)-->3CO2(g)+4H2O(l) Also, I'm not sure but when we're evaluating questions like these, do we count the number of moles only of solids, aqueous and...
  41. ~christina~

    Aqueous solutions and whether they are acidic/basic/neutral

    This isn't a homework question but a general question which I should know the answer to but am not sure. If you have a basic/acidic compound and add it to water to form an aqueous solution, the water should turn basic/acidic respectively, right? no exception? Thank you
  42. N

    Solubility of Aniline and Acetanilide in aqueous HCl?

    Hi Everyone! Hopefully someone can help me out with this question...Why is aniline soluble in aqueous hydrochloric acid, but acetanilide is not? Is it because aniline has a lone pair on the nitrogen that is more available to react? The lone pairs in acetanilide are too tied up with...
  43. S

    Recovering KNO3 from Aqueous Solution at 10°C

    Homework Statement The mass of potassium nitrate that could be recovered from a solution prepared at 60deg Celsius from 250g potassium nitrate and 250g water by cooling the solution to 10 deg Celsius. Homework Equations The Attempt at a Solution not to sure how to start this one...
  44. A

    Ammonia acts as a base in aqueous solution

    Homework Statement Ammonia acts as a base in aqueous solution; Kb is equal to 1.8 x 10-5. What is the Ka for the ammonium ion NH4+ in aqueous solution? Homework Equations The Attempt at a Solution I am totally lost for this question, can someone please start me off? all i know...
  45. A

    Solving a pH 10.7 Aqueous 0.250M NaOH & 5.00 L

    Homework Statement How would you prepare 5.00 L if an aqueous solution having a pH = 10.70, if you had a supply of 0.250 M NaOH? Homework Equations I don't even know anymore... The Attempt at a Solution I've tried a million different ways but I never come up with the answer...
  46. X

    Explain Why 1 Molar NaOH is More Concentrated Than 1 Molal NaOH Aqueous Solution

    Which one has a greater concentration, 1 molar NaOH or 1 molal NaOH aqueous solution? for the answer Explain Why!
  47. B

    Classifying Aqueous Solutions: Acids, Bases, or Neutral?

    Homework Statement Classify each of these aqueous solutions as acidic, neutral, or basic. A. HI(aq) B. NaCl(aq) C. RbOH(aq) Homework Equations The Attempt at a Solution A. HI(aq) is acidic B. NaCl(aq) is neutral C. RbOH(aq) is basic Am I right, wrong?!
  48. M

    Lovastatin in dilute aqueous acid

    Homework Statement If Lovastatin were heated in dilute aqueous acid, what would the molecular weight of the product be? (The large of the two products. Assume that there is no hydration of the alkene functionalities.) Homework Equations N/A The Attempt at a Solution I drew...
  49. J

    Preparing Aqueous Solutions for Chemistry Students

    Chem problem need help... Homework Statement How would you prepare the following aqueous solutions? (a) 1.10 kg of 0.0515 m ethanol (C2H5OH) from ethanol and water Add___ g C2H5OH to ____ g H2O. (b) 511 g of 15.0 mass % HCl from 35.3 mass % HCl Add___ g of 35.3% HCl to ___ g of water...
  50. K

    Potassium Permanganate Reduction in Aqueous Buffer

    Hello everybody, I'm told that potassium permanganate is dissolved in an aqueous buffer of ammonia and ammonium at equal concentrations (1M), and treated with 1M sodium hypochlorite, the permanganate ion is reduced to insoluble manganese dioxide as the hypochlorite ion is oxiddized to...