Questions tagged [aqueous-solution]
For questions relating to compounds dissolved in water and resulting reactions.
888
questions
2
votes
1answer
38 views
Accurate method to calculate the pH of a salt from a weak acid and weak base
Can someone help me with this?
The problem is as follows:
Find the $\mathrm{pH}$ of $\pu{1M}$ solution of $\ce{NH4CN}$. Their respective
hydrolysis constants are:
$K_h = 5.6\times 10^{-10}$
...
-1
votes
2answers
50 views
Solubility of Calcium Acetate [closed]
I am trying to dissolve 30 gram of Calcium Acetate (Hydrate) in 100 ml of distilled water. The calcium acetate is not going into solution. I am wondering if this is an issue with the distilled water....
0
votes
1answer
77 views
Why did they ‘split’ this H2+ ion in the ionic equation?
I am asked this chemistry question in my textbook:
Write an ionic equation for this reaction:
$$\ce{Mg(s) + H2SO4(aq) -> MgSO4(aq) + H2(g)}$$
This is my thought process and answer:
$\require{...
-1
votes
0answers
22 views
Solution Question
This is the question. Part a is easy. But I am confused about parts b and c. According to the answer key below, in order to calculate ppm you need to find the molecules of NH3 and molecules of air. I ...
3
votes
1answer
111 views
Can ionic compounds dissolved in organic solvent conduct electricity?
Ionic compounds dissolved in water, as an aqueous solution, can conduct electricity.
Can they conduct electricity if they are dissolved in organic solvent?
1
vote
0answers
20 views
Can Methylene Blue Detect Spoilage in Food?
Initially, there is already a product which is a sensor based on Methylene Blue, which can detect changes in oxygen levels in a packaging. However, as our thesis project, we decided to take on this ...
0
votes
0answers
16 views
How to find the molar concentration of two compounds mixed together in a buffer solution having the Kb and its Ph [duplicate]
Calculate how many milliliters of a $\pu{8.00 \times 10^{−1} M}$ solution of $\ce{NH3}$ and how many milliliters of a $\pu{7.80 \times 10^{−1} M}$ solution of $\ce{NH4Cl}$ are needed to get to a liter ...
0
votes
1answer
31 views
Is the solution isotonic, hypertonic, or hypotonic?
The problem is shown below. I don't understand how can the tonicity of a solution be determined if the solution has multiple solutes dissolved in it.
Do I take the total sum of the mass of solutes ...
1
vote
1answer
128 views
Elevation in boiling point of water [closed]
$\pu{1060 g}$ of urea aqueous solution is subjected to heating. It starts boiling at $\pu{100.53 °C}.$ It is heated up to $\pu{102.12 °C}.$ Find amount of water vapourised in grams. (Pure water ...
1
vote
1answer
35 views
Up to which dilution can one assume that 1 mg/l = 1 ppm?
For aqueous solutions it is often assumed that 1 milligram per liter equals 1 ppm. Are there any guidelines up to which concentration this shortcut is admissible?
Are there any formulas which ...
-1
votes
2answers
73 views
Lithium oxide is a base, but lithium alone is not. Why? [closed]
When lithium oxide reacts with water, it is said to be a base:
$$\ce{Li2O + H2O -> 2 LiOH + H2}$$
When lithium metal reacts with water, it is not considered a base:
$$\ce{2 Li + 2 H2O -> 2 ...
1
vote
2answers
92 views
How can iodine oxidise hydrogen peroxide?
The following is mentioned in NCERT (government textbook in India used in all schools) under chemical properties of $\ce{H2O2}:$
(iv) Reducing action in basic medium
$$\ce{I2 + H2O2 + 2 OH- -&...
2
votes
0answers
15 views
Competing half reactions in electrolysis of aqueous solution of sodium hydroxide
If you run a direct current using pure nickel electrodes through a solution of NaOH in distilled water, you will separate the water into hydrogen and oxygen.
Are there any other reactions that could ...
0
votes
1answer
34 views
Finding Ka of a monoprotic weak acid from pH and concentration of added sodium salt
A solution of $\pu{0.36 M}$ of the sodium salt of a generic monoprotic weak acid $\ce{HA}$ has a $\mathrm{pH}$ value of $8.782.$ $K_\mathrm{a} = ?$
Why doesn't the following formula work in this ...
0
votes
2answers
56 views
pH of amphoteric species
For a solution of $\ce{HA-}$, I have seen the following approximations for the $\mathrm{pH}:$
$$\mathrm{pH} = \frac{1}{2}(\mathrm{p}K_\mathrm{a1} + \mathrm{p}K_\mathrm{a2})\tag{1}$$
$$\mathrm{pH} = \...
1
vote
3answers
75 views
Tap water pH adjustment using citric acid
I've lowered tap water pH from 7 to 6 using citric acid. After couple of hours pH raised again to 7.
What is the reason for this raise? Citric acid overcomes waters buffering feature then raise the $...
0
votes
2answers
69 views
Acidic nature of boric acid when its concentration high
Following statement was given for boric acid $(\ce{H3BO3}):$
At low concentrations $(\leq\pu{0.02 M})$ essentially $\ce{B(OH)3}$ and $\ce{B(OH)4-}$ are present, but at higher concentration the ...
-3
votes
2answers
39 views
How would I separate a solution of sodium iodide and water in order to obtain the sodium [closed]
I am an amateur in this field of science and I am trying to separate a solution of Sodium Iodide and water. How would I separate the solution so I can obtain sodium?
1
vote
0answers
20 views
Stability of cuprous iodide in aqueous solution
An aqueous solution of $\ce{Cu+}$ is usually unstable, but $\ce{CuI}$ is stable. Explain. $E^\circ(\ce{Cu^2+/Cu+}) = \pu{0.153 V}$ and $E^\circ(\ce{Cu+/Cu}) = \pu{0.521 V}.$
I found this question ...
2
votes
1answer
73 views
Finding the concentration of each ion in saturated solution of lead(II) hydroxide
Question
If the solubility of $\ce{Pb(OH)2}$ is $\pu{0.155 g/L},$ then the concentration of each ion in a saturated solution of $\ce{Pb(OH)2}$ is
A. $[\ce{Pb^2+}] = \pu{0.155 g/L}$ and $[\ce{...
3
votes
2answers
158 views
Use of Concentration for pH
When we find the pH of a solution, do we use normality or molarity? My teacher said that if the compound is present by itself, we can use normality but in all other cases we should use molarity. Can ...
0
votes
1answer
85 views
Calculating pH of rain water
The concentration of $\ce{SO2}$ in the atmosphere over a city on a certain day is $\pu{10 ppm}$. Given that solubility of $\ce{SO2}$ in water is $\pu{1.3653 mol L-1}$ and $\mathrm{p}K_\mathrm{a}$ of $\...
2
votes
2answers
67 views
Calculating equilibrium concentrations of silver and halide ions
$\pu{500 ml}$ of $\pu{0.01 M}$ $\ce{AgNO3}$ is mixed with $\pu{500 ml}$ of solution containing $\pu{0.1 M}$ $\ce{NaCl}$ and $\pu{0.1 M}$ $\ce{NaBr}$. $K_\mathrm{sp}$ of $\ce{AgCl}$ is $10^{-10}$ and $...
4
votes
1answer
184 views
Is chromate a suitable indicator for the titration of Ag⁺ with Cl⁻?
To titrate $\ce{Cl-}$ with $\ce{Ag+}$ we use chromate $\ce{CrO4^2-}$ as an indicator.
The titration reaction is:
$$\ce{Ag+ + Cl- <=> AgCl}\tag{R1}$$
$$K_1 = \frac{1}{K_\mathrm{sp}(\ce{AgCl})} =...
4
votes
2answers
366 views
Taking volume contraction into account when mixing water with ethanol
To calculate the amount of purified water and the amount of ethanol (96% Vol.) which is needed for a desired/variable amount of a mixture - given a desired/variable percentage of ethanol - I use the ...
-1
votes
1answer
64 views
Hydrolysis of sodium carbonate [closed]
This is the equation given by my textbook for hydrolysis of sodium carbonate:
$$\ce{Na2CO3 + 2 H2O -> H2CO3 + 2 Na+ + 2 OH-}$$
and it mentions that sodium ion $(\ce{Na+})$ does not tend to ...
0
votes
1answer
39 views
Why is CO2 more likely to dissolve in a basic solution than an acidic solution? [closed]
I'm having trouble thinking through this problem. I know that when $\ce{CO2}$ dissolves in water it can release $\ce{HCO3-}$ and $\ce{H+}$ and cause a drop in pH. But can I use this to justify why $\...
-1
votes
1answer
31 views
What formula allows adjusting balance of (Ethyl Alcohol / Water / Caffeine powder) to know concentration for the Caffeine solution?
I am experimenting with different levels of concentrated caffeine solution. The solution has a small percentage of ethyl alcohol, in the $\ce{H2O}$.
Problems encountered too much ethyl alcohol ...
0
votes
0answers
28 views
Is an aqueous solution of calcium chloride hygroscopic?
Calcium chloride is deliquescent, it is hygroscopic, so much so that it dissolves in the water it has attracted by hygroscopy.
Sulfuric acid is hygroscopic, even if not anhydrous. So a solution ...
1
vote
3answers
77 views
Electrochemistry conditions for voltage to increase in a galvanic cell
I understand that increasing the concentration of reactants in a galvanic cell generally causes the voltage of the cell to increase. But is that really the case always?
Consider a standard cell of ...
1
vote
0answers
20 views
Stable physiological buffer to make NAD+ solution
I was wondering what would be the most stable physiological buffer for nicotinamide adenine dinucleotide (NAD+), for potential storage as frozen aliquots - 6 months stability or around there would be ...
0
votes
0answers
24 views
How to calculate the temperature change when CaCl2, NaCl, and water added together at an initial temperature of 298 K?
My question: How to calculate the temperature change when adding $\pu{0.1 kg}$ of $\ce{CaCl2}$ and $\pu{0.1 kg}$ of $\ce{NaCl}$ to $\pu{1 kg}$ water with an initial temperature of $\pu{298 K}$?
I ...
0
votes
0answers
40 views
Is contribution to pH by an acid or base always greater than salt hydrolysis?
I was solving a titration question and the reaction I came to was this:
$$
\begin{array}{lcccc}
\ce{&BOH(aq) &+ &HCl(aq) -> &BC(aq) &+ &H2O(l) }\\
\text{Initial} & x &...
2
votes
1answer
174 views
Solution of very small particles with neutral buoyancy and distinguishable to the naked eye [closed]
I'm trying to study the Tea leaf paradox, and asked a question about it on physics.stackexchange.com. To get further on the problem, I want to make a solution of very small objects in water that are ...
2
votes
1answer
104 views
What happens when ferric chloride is dissolved in water?
Ferric chloride can be prepared by dissolving hematite in hydrochloric acid:
$$\ce{Fe2O3 + 6HCl -> 2FeCl3 + 3H2O }\tag{1}$$
But the resulting ferric chloride will be exposed from its formation to ...
-1
votes
1answer
75 views
Is it possible to prepare a 0.1 N solution of HCl and methanol? [closed]
In my lab guide I read: "Use a $\pu{0.1 N}$ solution of methanol-chloridic acid $(9:1)$ for the anthocyanin extraction", so I tried to calculate the volume of $\ce{CH3OH}$ and $\ce{HCl}$ to prepare it,...
1
vote
1answer
134 views
Can acid-base reactions occur in a non-aqueous medium?
To better illustrate my question, allow me to refer to the case of ammonium chloride, formed through a classic acid-base reaction.
The reaction between ammonia and hydrogen chloride to give ammonium ...
1
vote
0answers
65 views
What is the pH and pKa relationship of LaCl3 in water and its precipitant La(OH)3?
In light of this question and its answers, I hope to get some insights into the $\mathrm{pH}$ of $\ce{LaCl3}$ in water and its $\mathrm{pH}$ relationship to $\ce{La(OH)3}$ precipitant's $\mathrm{p}K_\...
0
votes
0answers
50 views
Hydronium ion concentration to compare pH values
I'm having a bit of trouble with this question:
Which has a higher $\mathrm{pH}$ value, $\pu{0.001 M}$ $\ce{HCl}$ or $\pu{0.1 M}$ $\ce{CH3COOH}$ $(K_\mathrm{a} = \pu{1.8E-5})?$
I have calculated ...
0
votes
1answer
74 views
Meaning of mass concentration “units” % m/v [closed]
In a saline solution that is 5.750% (m/v) potassium iodide $(\ce{KI}),$ there are:
a) 5.750 mL $\ce{KI}$ per 100.0 mL $\ce{H2O}$
b) 575.0 mg $\ce{KI}$ per 10.00 mL of $\ce{KI}$ solution
c) 5....
1
vote
2answers
52 views
Predicting a precipitate based on Ksp
$\pu{105 mL}$ of $\pu{0.10 M}$ $\ce{AgNO3}$ is added to $\pu{125 mL}$ of $\pu{0.35 M}$ $\ce{K2CrO4}.$ Will a precipitate form? $(K_\mathrm{sp}$ for $\ce{Ag2CrO4}$ is $\pu{1.12E-12}.)$
Answer:
Can ...
3
votes
1answer
74 views
Gibbs energy derivative vs equilibrium for aqueous reaction
I am trying to find the Gibbs-energy equilibrium for the reaction $$\mathrm{A}+\mathrm{B}\rightleftharpoons\mathrm{C}.$$ According to most sources the equilibrium concentrations in an ideal solution ...
0
votes
0answers
17 views
What is the justification for using the Marcus rate equation to model charge transport in organic semiconductors?
I am trying to understand the history of how Marcus theory moved from describing electron exchange reactions in aqueous ionic solutions to also being applied to describe transport in organic ...
0
votes
1answer
47 views
How to know which reduction and oxidation reactions occurred?
We just had a lab experiment on galvanic cells and we used 0.5 M and 1 M iron(III) nitrate solution at the anode (iron electrode) and 1 M and 0.5 M copper(II) nitrate solution at the cathode (copper ...
1
vote
0answers
28 views
Calculating pH of a saturated weak acid/base solution [closed]
How can you calculate the $\mathrm{pH}$ if you know for example the $\mathrm{p}K_\mathrm{a}$ or $\mathrm{p}K_\mathrm{b}$ value of a weak acid/base and how much acid/base can dilute in water. Let's ...
0
votes
2answers
58 views
Why do we use [H⁺] and [OH⁻] in balancing redox reactions instead of using [H₃O⁺] and [OH⁻]? [duplicate]
For what reason is it universally agreed upon that we use $$\ce{H+ + OH-}$$ ions in balancing water on either side of the reaction, but not the $$\ce{H3O+}$$ ions?
2
votes
0answers
40 views
Do I understand correctly that simulation volume influences relative permittivity calculations? If so, how is the result useful?
I am having a lot of trouble understanding the influence of volume on relative permittivity/static dielectric constant. I'm not a chemist, but am using molecular dynamics to calculate relative ...
-1
votes
1answer
44 views
How to find osmolarity of a solution contatining salt and glucose?
What is the osmolarity of a solution that contains $4.00\%$ (m/v) $\ce{NaCl}$ $(M = \pu{58.44 g mol-1})$ and $3.00\%$ (m/v) glucose $(M = \pu{180.18 g mol-1})?$
I know you have to convert percentages ...
2
votes
1answer
62 views
What is the interaction between dissolved ions of opposite valence in a solution at rest?
NaCl is dissolved in water. Ions sodium and chloride are sufficiently free from each other so that they may occupy different regions of the solution after an active transport process through a ...
0
votes
1answer
71 views
Isolating barium(II), copper(II) and zinc(II) from aqueous solution [closed]
Q15 Each metallic ion was separated from an aqueous solution containing $\ce{Ba^2+},$ $\ce{Cu^2+},$ and $\ce{Zn^2+}$ by the procedure shown in the following figure. From ①–⑥ in the table below choose ...
