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Questions tagged [acid-base]

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 on the other hand is a chemical species/ molecular entity having an available pair of electrons capable of forming a covalent bond with a hydron/ proton (Brønsted base) or with the vacant orbital of some other species (Lewis base).

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Buffer Solution with Strong Acid?

I was thinking: Could we could make a strong acid-strong base buffer solution? Take, for instance, a mixture of 1 L $\ce{HCl}$ (0.1 M) and 1 L of aqueous salt, $\ce{Na_2SO_4}$ (also 0.1 M), note that $...
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13 views

Using proton affinity to compare relative basicity of two molecules

I have a paper citing a proton affinity value for a heterocyclic molecule at ~1150 kJ/mol. Since I am unused to working with proton affinity, I would like to find a reference base to orient myself on ...
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1answer
631 views

How does H2SO4 dissociate?

Apologies for this extremely basic question, I'm just beginning with Chemistry so please don't be too harsh on me. My book says that sulfuric acid, $\ce{H2SO4}$, dissociates in its ions following ...
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1answer
230 views

Finding the pH value of HF [closed]

Find the pH value of HF. $pH = -\log[H+]$ for strong acids $pOH = -\log[OH-]$ for strong bases $pH = 1/2(pKa - \log C)$ for weak acid $pOH = 1/2(pKb - \log C)$ for weak base HF is weak acid so $...
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1answer
60 views

What happens to an acid when it completely dries out?

What happens to an acid when it completely dries out? Does it stop being acidic? And if there is a base there also, does it give back it's H's?
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1answer
38 views

How come one of the hydroxides in the phosphate group are more acidic than the other?

Three phsiologically relevant $\mathrm{p}K_\mathrm{a}$ values are associated with psilocybin: 1.3, 6.5 and 10.4. Suggest the appropriate charged species and mark the $\mathrm{p}K_\mathrm{a}$ values ...
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1answer
167 views

Why do my equilibrium calculations on this HF/NH4OH buffer system not match those in literature?

I've been trying to reproduce Figure 2 from this research paper (full text available). The Problem However I can't seem to get the same values as in the paper. I did the math both by hand and with ...
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1answer
92 views

Can someone confirm and/or correct my logic regarding this mechanism?

In the picture, Ethyl 2-oxocyclopentanecarboxylate (I) reacts with ethyl 2-(4-chloromethylphenyl)propionate (II) in the presence of KOH in hot DMF to afford ethyl 2-[4-(1-ethoxycarbonyl-2-...
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1answer
88 views

Comparing the pKb of piperazine and methylpiperazine

In comparison to piperazine, the inductive effect will cause the $\mathrm{p}K_\mathrm{b}$ of methylpiperazine to be: The answer given is that the $\mathrm{p}K_\mathrm{b}$ will be lower due to ...
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1answer
86 views

What are the predominant acids in sphagnum peat moss?

I'm trying to figure out what the predominant acidic substances in peat moss are. Peat moss is said to have a pH of approximately 4.0. So, I'm curious what is making it acidic. I know not all acids ...
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0answers
95 views

How to check which compound is amphotheric,neutral,basic or acidic among - (ZnO ,Al2O3,PbO,Cr2O3,BeO,SnO,CO2,CO,NO,NO2)? [closed]

A lot of questions are asked on the nature(acidic,basic,neutral) of compounds in exam.How can I solve such questions ? without memorizing its nature is there any way to solve? please explain how to ...
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1answer
139 views

Why does hydrolysis of OF2 give a neutral solution?

I found this equation on the internet for the hydrolysis of $\ce{OF2}$: $\ce{OF2 + H2O -> HF + O2}$. So, according to me, $\ce{HF}$ must make generate an acidic instead of neutral solution. But ...
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1answer
373 views

How can Arrhenius bases also be Brønsted-Lowry bases?

According to ChemGuide, The Brønsted-Lowry theory doesn't go against the Arrhenius theory in any way - it just adds to it. According to Study.com: All Arrhenius acids and bases are also ...
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1answer
58 views

Lewis Acid/Base Chemistry

I'm looking for some clarification on Lewis Acid/Base Chemistry. For the Acids do they have to accept a full pair of electrons to be considered a Lewis acid, or do they just have to accept an ...
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2answers
152 views

Why do most carboxylic acids have high pKa (~5) in spite of having a conjugate base ion that is stabilized by resonance?

This is from my textbook: Carboxylic acids owe their acidity ($\mathrm pK_\mathrm a$ of about $5$) to the resonance-stabilized carboxylate anions formed by deprotonation. Why are they such weak ...
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1answer
153 views

How to calculate the equilibrium constant of acetic acid-hydroxide ion equilibrium?

I am trying to calculate the equilibrium constant of the following equilibrium: $$\ce{CH3COOH (aq) + OH- (aq) <=> CH3COO- (aq) + H2O (l)}$$ I am aware that this reaction essentially goes to ...
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1answer
89 views

are half of “H2SO4 pH sample problem” webpages just wrong, or am I wrong?

I did a Google search for "h2so4 pH sample problem" and went through the results, and it looks like about 50% of the webpages "explaining" how to do this problem give the wrong answer when calculating ...
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0answers
46 views

Buffer solutions

So my understanding of buffer solutions is that when a strong acid is added, it will react with the conjugate base to convert the strong acid to a weak acid. The weak acid then dissociates to reform ...
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1answer
175 views

Evaporation of concentrated formic acid and semi-concentrated sulfuric acid at room temperature

I recently looked at a reaction where CO is synthesized using formic acid and sulfuric acid, which seems to be one of the easier to control reactions for this, and obviously ventilation etc is ...
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1answer
43 views

Why do we use different arguments for determining the strength of hydracids and solubility of ionic compounds?

HI is a stronger acid than HF. Why? Because when dissolved in water, the bigger iodide ion handles the negative charge way better than the small fluoride ion. So Iodide ion is a weak conjugate base ...
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144 views

pKa Values and the Leveling Effect

I've heard that the leveling effect happens if the pKa of the acid is less than water, but then I've also heard it will happen if the acid is too strong (stronger than Hydronium). Is this correct? Are ...
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1answer
256 views

Calculating PH of solution after adding strong acid (equilibrium)

Consider the classic example when talking about acids and bases: Say you have 1M of $\ce{HCL}$ and you throw it into water, calculate the resulting pH (= concentration of $\ce{H3O+}$). The way this ...
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9answers
8k views

Would it be possible to destroy gold?

I'm a writer. I have a scenario in which a sizable amount of gold needs to be rendered unusable, preferably completely destroyed. I know an acid like aqua regia is able to dissolve gold, but would ...
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0answers
65 views

Two differing methods for vanadium extraction

The following sources (Source 1, Source 2) both cover the extraction of Vanadium (specifically Vanadium Pentoxide, $\ce{V2O5}$) from petroleum residue (petcoke and flyash respecitvely). However when ...
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2answers
223 views

How to determine the order of acidity of the following dimethyl nitrophenols

This is how I went about it, although I got a wrong answer: 3,5-Dimethyl-4-nitrophenol (2) shows the nitro group to be sterically hindered, due to which it should go out of plane and this will be an ...
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1answer
78 views

Determining volume of acid needed to be added to reach a specific pH

Suppose there are $\pu{0.024}$ moles of $\ce{Na2HPO4}$ in a $\pu{0.250L}$ solution. How would we calculate the amount of $\pu{0.145M}$ $\ce{HCl}$ needed to reach a $\mathrm{pH}$ of 6.60? I have ...
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1answer
37 views

Why does pH increase as a weak acid becomes more dissociated?

My Organic Chemistry (Wade, 9th ed) textbook mentioned the following note: "In most cases, the pKa of an acid corresponds to the pH where the acid is about half dissociated. At a lower (more acidic) ...
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1answer
78 views

What mass of potassium lactate is needed to 300.0 mL of 0.238 M Lactic acid solution to make a solution with a pH of 4.00? pKa (lactic acid) =3.86

Upon attempt, I've yielded an answer of 11.91g. My calculations do not take 300 mL Lactic acid solution into account, and now I somewhat know the error is at least partially due to the fact that my ...
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2answers
174 views

Why is acetone less acidic than cyclohexanol?

The $\mathrm{p}K_\mathrm{a}$ of acetone is 19, whereas the $\mathrm{p}K_\mathrm{a}$ of cyclohexanol is 16. However, acetone is resonance stabilized and its major resonance structure displays the ...
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1answer
515 views

Is Sodium Hydroxide a Bronsted-Lowry Base?

I know that sodium hydroxide dissociates into sodium cation and hydroxide, so it must be an Arrhenius base. I am also aware of the rule that all Arrhenius acids and bases are considered to be Brønsted-...
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113 views

Predicting products of chemical equations? [duplicate]

Consider the equation $\ce{2 NaOH (aq) +Cl2 (g) —> NaOCl (aq) + NaCl (aq) + H2O (l)}$. How would one know the products of this reaction? Is there a general way of doing this? I would have no ...
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1answer
42 views

Why can't negative charge on a carbon have resonance with a neighboring alcohol?

In these resonance forms of a conjugate base of ascorbic acid, why can't the electrons on the negatively charged carbon in the third form be used to form a double bond with the alcohol and thus ...
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0answers
24 views

How would you make a pH 6 tetraborate buffer using NaOH?

I'm helping a Grade 11 student doing an EE on determining lead soil content. We found a good, doable procedure for it, but one of the reagents is a borate buffer that doesn't seem to have a recipe ...
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2answers
235 views

Comparing basic strength of nitrogen heterocycles

Compare the basic strength of the following compounds: d > b > c > a c > b > a > d c > a > b > d a > d > c > b I know that in compound (c), the π-bond between nitrogen and ...
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31 views

Buffer/ Indicators / % protonated

I have a buffer with a pH of 5. First I need to find what indicator to use. My options are (Thymol Blue - $\mathrm{p}K_\mathrm{a} = 8.9$), (Bromothymol Blue- $\mathrm{p}K_\mathrm{a} = 7.1$), or (...
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1answer
170 views

Preparing 1M acetic acid buffered with 1 M Ca-acetate to specific pH

I am prepping a buffer solution of 1M acetic acid and 1M calcium acetate with a pH of 5, but it has been a long time since chem 101. I have some notes from an old lab mate that suggested that 600mL of ...
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40 views

How can the CO2 released from sodium bicarbonate reacted with HCl lift an alginic raft if the sodium bicarbonate acts first?

In the antacid Gaviscon, sodium alginate reacts with hydrochloric acid and then calcium carbonate to form an alginic raft that is supposed to be lifted to the top of the stomach by the carbon dioxide ...
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1answer
34 views

Titrations in three equibilums

You have three solutions: 0.1 M solution of a weak monovalent acid 0.1 M solution of a strong monovalent acid 0.1 M solution of a weak divalent acid Each solution is titrated with 0.15 M NaOH. What ...
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2answers
616 views

Is sodium acetate a neutral or a basic salt?

I read somewhere that salts which do not contain a replaceable hydrogen or hydroxyl group are classified as normal salts. But I also know that strong base-weak acid salts are basic in nature.
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80 views

If i keep adding sulfuric acid into water, will it keep dissolving forever?

If i keep adding sulfuric acid into water, will it keep dissolving forever?
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1answer
91 views

Examples for oxidation of fluoride and for fluoride as a base

I have no university degree in chemistry and I’m curious about some examples - explained with the applicable rules (or the exception from the existing rules) - for the following statements (from this ...
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0answers
396 views

How does dilution affect the pH of a solution of a weak acid(or base)?

There is a rule that says "Diluting a weak acid increases its pH (towards 7)" and another rule saying that according to Henderson's relation upon diluting a solution of a weak acid and its conjugate ...
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1answer
89 views

Why does nitric acid have a different molecular structure from phosphoric and arsenic acids?

I remember that this really bugged me as an undergrad, and upon revisiting some inorganic chemistry notes I realized I still don't have a satisfactory answer for it. The structure of nitric acid, $\ce{...
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1answer
63 views

Different HCl concentrations and iron nails [closed]

Hey guys I am at high school and we have a project on designing our own lab. My questions is will different concentrations such as 10%, 20%, 30% and 37% have an affect on the corrosion of an iron ...
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2answers
238 views

Basicity comparison of ammonia derivatives (and guanidine)

Arrange the following in decreasing order of basicity: $\ce{N(CH3)3}$ Guanidine $\ce{N(C6H5)3}$ $\ce{NH(CH3)2}$ My answer - 2 > 1 > 4 > 3 Option '2' due to equivalent resonance ...
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0answers
82 views

What is first protonated aldehyde or lactone?

In a six membered lactone with carbaldehyde in beta position, which oxygen gets protonated first? the lactone or the aldehyde? (Using concentrated HCl)
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33 views

No phenolphthalein mono-anion?

This is a follow-up to the question here. There is no mono-anionic stage shown, does it "disproportionate" to the neutral molecule and the di-anion?
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1answer
109 views

How many protons does phenolphthalein lose in basic solutions?

So, I've looked it up and Wikipedia claims that two protons are released by Phenolphthalein when pH is over 8.2, but I've seen other sources that claim only one proton is lost. So, is it really just ...
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2answers
87 views

Why is it that all strong bases contain at least one hydroxide bond?

Why is it that all strong bases contain at least one hydroxide bond? What is going on here at the chemical level? For example, we know that $\ce{NaOH}$ is a strong base. I know it is strong because it ...
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2answers
160 views

Are the best buffers those that are in a 1:1 ratio with its conjugate acid/base?

I wanted to comment this, but I don't have enough reputation, so I just made this a question. I know that buffers and their conjugate base/acid must exist in similar amounts for the buffer to be ...