This tag should be applied to questions concerning acid and base reactions. An acid is capable of donating a hydron/ proton (Brønsted acid) or capable of forming a covalent bond with an electron pair (Lewis acid). A base is on the other hand a chemical species/ molecular entity having an available ...

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write an equation for an acid-base reaction

write an equation for the reaction you might expect to take place if trichloroethanoic acid, $\ce{Cl3CCO2H}$, (pKa=0.65) were added to dimethylpropanoic acid, $\ce{(CH3)3CCO2H}$ (pKa=5.05). explain ...
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What volume of 0.300N NaOH would be needed to bring 16.0mL of distilled water that has a pH of 7.00 to a new pH of 12.42?

This is my attempt at a solution: NaOH + H20-> Na + +OH- + H2O pH= 7.00 pH= 12.42 pH= -log[H+] [H+]= 10^-7.00 = 1x 10^-7 ions 0.300N (ions/L) V1= 0.016L C1= (0.300ions/L)(1x10^-7)= 3x10^-8 N ...
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18 views

Higher E HOMO of two Lewis bases

Given borane's ($\ce{BH3}$) LUMO, which of these Lewis bases would have a more stabilizing interaction? In acid bases that means the higher HOMO and lower LUMO equals a stronger dative bond I ...
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0answers
17 views

Working out the number of Moles adsorbed of Ethanoic acid

I'm currently trying to work out the Freundlich isotherm constants of Ethanoic Acid or Acetic acid. The equation is $$\frac{X}{M}=AC^{(1/n)}$$ with X being number of moles of acid that are adsorbed, ...
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1answer
49 views

Calculating concentration and volume in acid metal reactions [on hold]

In the reaction: $$\ce{3 Zn + 2 H3PO4 -> Zn3(PO4)2 + 3H2}$$ I know the initial mass of $\ce{Zn}$ to be 13.08 g and the volume of phosphoric acid to be 0.5 $\mathrm{dm^3}$. How do I work out the ...
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0answers
11 views

Chemistry of sodium dihydrogen phosphate [on hold]

How much sodium dihydrogen phosphate/monobasic sodium phosphate $\ce{Na2HPO4.3H2O}$ needs to be added to 1 litre of pH 9.5 water to lower the pH to 8.5?
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7 views

How can I determine the molarity of a base solution using the volume and molarity of the acid? [on hold]

Molarity of Acid = 0.1687 M Volume of acid = 25 mL Volume of base needed to neutralise acid = 19.56 mL If you could explain procedure would be great!
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1answer
45 views

Why is ionic strength (mu) calculated differently for these 2 examples?

In the following examples; I don't understand why $\ce{Na_3PO_4}$ is a much more complicated process when calculating $\mu$ compared to $\ce{NaH_2PO_4}$ and $\ce{Na_2HPO_4}$. Specifically, I don't ...
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1answer
29 views

Henderson Hasselbach Equation

So will the hasselbach equation be able to calculate the pH when you have an acidic solution and you add a basic solution? Will that be possible or should you must add only add an acid to calculate ...
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0answers
22 views

How to calculate the sulfanediide concentration at equilibrium in a saturated hydrogendisulfide solution at pH 6? [on hold]

What is the $\ce{S^{2-}}$ concentration in a saturated solution (0.10 M) of $\ce{H2S}$, in which the pH has been adjusted to 6.00 by the addition of $\ce{HCl}$? For $\ce{H2S}$, $K_{a1} = 1.1 \cdot ...
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2answers
46 views

How to calculate pH of a solution with two dominant equilibria?

Say you have acid X for which $K_a(X)$ = 1E-7 and acid Y for which $K_a(Y)$ = 0.8E-7. In separate solutions, it would be easy to calculate $[H^+]$ because there would be only one dominant equilibrium. ...
3
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1answer
67 views

How do I know that an acid and conjugate base are present in equimolar amounts?

Acetylsalicylic acid is a molecule in several popular drugs such as Magnyl and aspirin. Its pKa is 3.5, and I'm about to calculate the pH of a 0.010 M solution of acetylsalicylic acid. I've read up ...
3
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1answer
327 views

Are all strong bases alkalis?

In my text book, it says that strong bases are alkalis because they fully dissociate in aqueous solution. But I'm not too sure of this. Can you not have a weak alkali? And can you not have a strong ...
3
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1answer
36 views

Calculating charge of amino acids (am I doing it right?)

Please consider this picture of a peptide chain: I've done some examining on the different amino acids and concluded that the chain is as follows: Lys-Leu-Gly-Ser-Citrullin (variant of arginine). ...
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1answer
24 views

Basicity of Group 15 hydrides [duplicate]

Why does the basicity of Group 16 hydrides ($\ce{NH_3,~ PH_3,~ etc}$) decrease down the group ? I know that its Lewis Base nature due to the lone pair but wouldnt the more EN element be less ...
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2answers
281 views

Storing large quantities of KOH

I need to handle large quantities of $\ce{KOH}$; close to 1000 liters of 85% conc $\ce{KOH}$ for about an hour. Any suggestions on how I go about doing it? Also the temperature during the process ...
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1answer
39 views

Which is more basic: aniline or pyridine? [closed]

Please explain why, thank you very much.
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2answers
43 views

Which pH indicator will give a dramatic color change with small changes in the amount of carbon dioxide dissolved in water?

I want to do a demonstration for students where they take a capped syringe and change the volume above a solution of seltzer water. The amount of carbon dioxide dissolved will vary, hopefully ...
3
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2answers
99 views

How can pKas differ across similar protons of the same atom?

For example, citric acid has three acidic protons, all of which are carboxylic acids. Despite being part of the same functional groups, they all have very different pKas. Why (and how?) is this?
4
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1answer
39 views

Can I make a buffer from two different weak acids or bases?

Can I make a buffer using two different acids/bases? For example, adding 1 mole of acetic acid and 1 mole of ammonia? The only information I can ever find is that I can make a buffer using only an ...
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1answer
16 views

Confused on normallity

So normality is 'equivalents' over liters solution right? I'm having a hard time understanding exactly what an equivalent is. At first from one thing I read i thought it was just the H released from ...
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1answer
48 views

Calculating the concentration of acetic acid in vinegar from pH

DavePhD was kindly helping me with this problem but the site indicated the discussion had gone on too long. Calculating vinegar strength I don't have enough units to start a chat so I am starting a ...
2
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2answers
54 views

Calculating vinegar strength

The pKa of vinegar is 4.76. If I know the pH of the vinegar, what would be the formula for determining the percentage acid base on the relationship between pH, pKa and concentration? Can you show the ...
3
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1answer
27 views

Carbonate + acid reactions - How to recognize these type of reactions?

So I've got $$\ce{CaCO_3 + HCl \rightarrow CO_2 + H_2 O + CaCl_2}$$ I'm wondering how I can recognize these types of reactions? I know that when I mix an acid and a base I get salt and water but in ...
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3answers
93 views

pKa differences and reactivity

I know a lot of chemists like to quote pKa values and subtract them to reinforce some notion about some acid-base reaction being highly favorable or highly unfavorable or whatnot. However, pKa ...
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1answer
46 views

Is there a relationship between bond strength and polarity?

I believe that a more polar bond would be stronger, since it would be similar to an ionic bond. However, this seems to be wrong when applied to the study of acidity of some compounds.
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1answer
47 views

Why is Ag+ a soft acid?

A soft species is typically large, polarizable and has a low charge (magnitude). The silver cation is not highly charged (this supports softness) however, it is anomalously small due to high nuclear ...
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1answer
21 views

What is buffer capacity and how can a buffer “run out”?

I'm a little confused on something: A buffer has a certain capacity and then runs out. But, if the buffer is given by: $$\ce{A- + H2O <=> HA + OH-},$$ when the $\ce{A-}$ reacts with the water, ...
1
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2answers
38 views

Why is it that weak bases usually contain a Nitrogen?

Why do weak bases usually contain a nitrogen, I know there are two electrons on top for a bond of H but why is it mostly nitrogen? I know there are other elemental bases too but why do I keep seeing ...
2
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1answer
25 views

Clarifications about acid-base theory

Considering the Arrhenius theory of acids and bases: Is every existing compound either an acid or a base? Why is a compound such as $ \ce {NH_3}$ considered a base, if it doesn't even have an ...
3
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2answers
430 views

What's the pH of Vinegar when it generally contains 5% Acetic acid?

Vinegar generally contains 5% Acetic acid. We would expect the pH of vinegar to be approximately: a. 0 b. 3 c. 7 d. 9 e. 12 I don't have the key for this question, so I ...
0
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1answer
31 views

What is the S2- in 0.10 M hydrogen sulfide?

I found this question in one of the problem sets and I decided to try it, I keep getting 9.1E-8 as the answer and I thought this since this is a diprotic acid and I made two equations and I keep ...
2
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2answers
243 views

Why is the second reaction being neglected?

If we want to find the concentration of $\ce{H+}$ ions at equilibrium when a weak conjugate base such as $\ce{C2H3O2-}$ added to water, why do we take the conjugate base reaction for calculation i.e ...
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1answer
40 views

How to calculate the pH of a citric acid solution after adding magnesium oxide? [closed]

$4.03~\mathrm{g}$ ($0.100~\mathrm{mol}$) of magnesium oxide is added to $100~\mathrm{mL}$ of a saturated ($4.00~\mathrm{mol\cdot L^{–1}}$) solution of citric acid. Calculate the pH of the resulting ...
4
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2answers
73 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 ...
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1answer
60 views

How strong is 2,4,6-trinitrobenzenesulfonic acid?

What is pKa or Hammett's function of 2,4,6-trinitrobenzenesulfonic acid? PubChem says 0.13 for pKa, but in what solvent? - I doubt it's a value for water. EDIT: If it is real value for water why ...
2
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1answer
19 views

How to make 0.3% ammonia water from 28-30% ammonia hydroxide

Can someone tell me how to make 0.3% ammonia water from 28-30% Ammonia hydroxide? I am trying to make a gallon or 3.78 Liters.
2
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1answer
13 views

Ion concentration in acid and base

Hello here is a question that is a bit confusing I hope you can help me solve it and understand it: Determine the hydromium and hydroxide ion concentrations in a solution that is $10^{-4} M \ce{ ...
2
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3answers
37 views

Why and when is lysine charged

I'm reading about Lysine and doing some calculations on it's charge under various $\ce{pH}$. Depending on the source, Lysine is usually stated as a charged amino acid with a $\ce{NH3+}$ group. ...
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2answers
40 views

Nascent Chlorine reactivity

What is the thing that makes nascent chlorine so reactive in a mixture of aqua regia so that its able to dissolve gold and silver?
2
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1answer
41 views

How to rationalise the protonation state of amino acids

I am learning about amino acids in various $\ce{pH}$ environments and how their groups are protonated or deprotonated in these environments. I don't need to mention a specific acid for my question, I ...
6
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2answers
82 views

Adding lemon to lentils changes color from black to pink, why?

I noticed that when I cook black lentils and add lemon juice to the water that's left, the water turns from black to pink! What can be the reason for that?
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1answer
44 views

What ratio of bicarb to vinegar do I need in order for the result to be ph neutral?

This question stems from the one I just asked over at cooking where my recipe tasted decidedly off because the pH was wrong. The recipe called for 16g bicarb of soda and 15g of vinegar (mine was 5% ...
2
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2answers
39 views

Which base is stronger methylamine or propylamine?

Which base is stronger methylamine or propylamine? I know that it depends on the strength of inductive effect of alkyl group. Am I right? But how can I determine the difference between methyl and ...
2
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1answer
42 views

Should the relatively low solubility of a base be considered in the calculation of the pH?

Hydrochloric acid, $V=75.0~\mathrm{mL}$, $c=0.250~\mathrm{M}$, is added to $225.0~\mathrm{mL}$ of $0.0550~\mathrm{M}$ $\ce{Ba(OH)2}$ solution. What is the concentration of the excess $\ce{H+}$ or ...
3
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2answers
59 views

Strong and Weak Acids/Bases

I'm so confused... $\ce{HClO}$ is a weak acid. then why is its conjugate base, $\ce{ClO-}$, a weak base in water? shouldn't they be inversely proportional? shouldn't $\ce{ClO-}$, be a strong base? ...
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2answers
123 views

What is the Ka of OH- and Kb of H3O+?

What is the $K_a$ of $\ce{OH^-}$ and $K_b$ of $\ce{H_3O^+}$? Have these constants been determined?
1
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1answer
57 views

How to calculate the concentration of all relevant species in a buffer of a given pH?

You prepare $1.0~\mathrm{L}$ of a $0.25~\mathrm{M}$ acetic acid solution with a final $\ce{pH}$ of $6.0$. What are the molar concentrations of all relevant acetic acid species ($[\ce{HA}]$ and ...
5
votes
2answers
104 views

Is Saliva an acid or base?

I have a debate with some friends who believe that saliva is just basic, but with the enzymes which make them reactive with objects in our mouth, shouldn't it be an acid in this case?
3
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1answer
79 views

What is a strong base?

How come that some insoluble compounds in water, e.g. $\ce{Mg(OH)2}$, $\ce{Ca(OH)2}$, $\ce{Sr(OH)2}$ are considered strong bases? Are they even strong bases? How can I tell if a compound is a strong ...