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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1answer
17 views

How to determine the pH of citrate buffer system

I used this table (http://microscopy.berkeley.edu/Resources/instruction/buffers.html) to make a citrate buffer system. The Pka value is 6.4, and I multiplied the solution by ten to make a larger batch....
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21 views

Why is H2Te the strongest acid among the following?

Among H2S, H2Se, H2Te the strongest acid is H2Te. The reason being that the bond strength in it the weakest so it dissociates easily. But my question is that why does it looses H+ in first place ...
5
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1answer
555 views

Which hydrogen of 3-methylcyclohex-2-en-1-one is the least acidic?

Which hydrogen of 3-methylcyclohex-2-en-1-one is the least acidic? According to me it should be 2, as on its removal there won't be any resonance stabilization as would happen in the other ...
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1answer
74 views

Difference of Ascorbic acid dissolved or precipitated in Glycerol?

Difference of Ascorbic acid (AA) dissolved or precipitated in Glycerol? Referring to pat US20110008445A1 Solution 1 At 25C, AA was dissolved in glycerol and alcohol (subsequently removed by ...
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28 views

How is HCl relevant in the reaction of iodomethane and ammonia? [closed]

The following reaction is conducted using $\pu{1.8 g}$ of $\ce{CH3I}$ and $\pu{250 mL}$ of a $\pu{0.2 mol L-1}$ solution of aqueous $\ce{HCl}$. $$\ce{CH3I (l) + NH3 (aq) -> CH3NH2 (aq) + HI (aq)}$...
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2answers
3k views

Why is water ignored in the ionic equilibrium of HF?

While trying to understand the solution of a problem given in my textbook, I realized I'm having some difficulty with the solution. The problem is as follows: The ionization constant of $\ce{HF}$ ...
5
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3answers
399 views

Am I understanding buffering capacity against strong acid/base correctly?

I just want to make sure I'm understanding buffering capacity correctly. I've been working on this problem: Suppose you have an acetic acid buffer, $\mathrm{p}K_\mathrm{a} = 4.74$, at the ...
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2answers
51 views

Acidic strength comparison between sulphuric acid and nitric acid

Why is $\ce{H_2SO_4}$ more acidic than $\ce{HNO_3}$. Shouldn't it be the other way around because $\ce{N}$ is more electronegative than $\ce{S}$? My reason: $\ce{O}$ can take electrons more easily ...
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19 views

Acid Value Analysis using Sodium Hydroxide instead of Potassium Hydroxide [closed]

I would like to ask about the acid value analysis using sodium hydroxide instead of the usual potassium hydroxide. If I use sodium hydroxide, do I use the relative molecular mass of sodium hydroxide ...
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3answers
2k views

Why oxides with the element in higher oxidation state are more acidic

We see this trend of acidic-basic property of oxides in most cases: $\ce{Mn2O7}$ is acidic, $\ce{MnO}$ is basic, the intermediate oxides are progressively less acidic and more basic, as the oxidation ...
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1answer
33 views

Why conjugate base/acid needed in buffer solution? [closed]

If I talk about the CH3COOH,CH3COONa acidic buffer solution , CH3COOH --> CH3COO- + H+ Why the conjugate salt is needed ?? Why it can't be like that the addition of extra H+/OH- neutralizes by ...
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1answer
1k views

Which proton is more acidic in this compound?

I'm having trouble determining which of these protons is more acidic. I was thinking the solution had something to do with the double bond in the aromatic ring, but I'm still not sure.
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1answer
4k views

Soap versus Shampoo

Soap and shampoo are both cleaning agents in our daily life. Why is soap in solid form and shampoo is in a liquid form, though? Is it because of the chemical components inside them or another factor?...
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9 views

Determination of a the concentration of phosphoric acid [closed]

in a question about ways to determine the concentration of phosphoric acid you mentioned adding a known amount of NaOH, measuring the pH and then calculating the amount of phosphoric acid. How do ...
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1answer
42 views

Why are alkali metal compounds like sodium hydride or sodium amide strong bases but weak nucleophiles?

I understand why compounds such as $\ce{NaH}$ or $\ce{NaNH2}$ are weak nucleophiles: as they aren't very soluble in organic solvents, they react only on the clusters' surface. But why are they strong ...
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2answers
3k views

What are the crystals that have formed around the top of a conc. nitric acid bottle?

I was looking through my chemicals cupboard and found that this decades-old bottle of conc nitric acid had grown a beard. I can't think of any reaction between (presumably) $\ce{NO2}$ and any airborne ...
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2answers
146 views

Why is d3-acetic acid more acidic than acetic acid?

The following table is from Solomons, Fryhle and Snyder Organic Chemistry, chapter 3, An Introduction to Organic Reactions and Their Mechanisms: Acids and Bases: Table 3.8 Isotopic substituents and ...
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1answer
215 views

Steric Inhibition of Resonance in ortho-substituted Benzoic Acids

It is given that due to Steric Inhibition of Resonance (SIR), the acidity of ortho-substituted benzoic acid increases with respect to benzoic acid. However, I'm unable to understand the reason behind ...
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21 views

How do you find the ph of lime juice through titration?

I am doing an experiment on the effect of time on the pH of Lime juice. I was wondering how you would calculate the pH through titrations using 1 Molar NaOH. I have been racking my brain on this for a ...
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25 views

i had a idea about how to make sulfuric acid and i wanted to know if this was true [closed]

I wanted to know, if i were to crush sulfur into really tiny pieces and mix them well with some hydrogen peroxide would sulfuric acid be made?
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30 views

Trends in the acid strength of oxoacids

I was working on a problem regarding the relative acidity of oxoacids in the form $\ce{HYO3}$ where $\ce{Y}$ represents a group 17 element. The question (which is from a worksheet created by a ...
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2answers
1k views

Acidity of cyclopentadiene when fused to benzene rings

Why does fusion to a benzene ring reduce the acidity of a cyclopentadiene ring? For example, acidity decreases going from cyclopenta-1,3-diene to indene and to fluorene:
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2answers
8k views

Why does having equivalent resonance structures give more stability?

Although the phenolate ion has more resonance structures (4) compared to acetate ion (2), acetate is more stable because it has two equivalent resonance structures of same energy. Why does having ...
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2answers
81 views

Why is H⁺ ion considered the source of acidity, and OH⁻ considered the source of basicity? [closed]

As the title implies, what caused the association between $\ce{H+}$ and acidity, and between $\ce{OH-}$ and basicity?
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3answers
782 views

Which of the following is the most acidic salt?

A 0.1 M solution of which salt is most acidic? (a) Aluminum(III) nitrate $\ce{Al(NO3)3}$; (b) Magnesium(II) bromide $\ce{MgBr2}$; (c) Sodium bicarbonate $\ce{NaHCO3}$; (d) Sodium formate $\...
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2answers
103 views

Gold refining using HCl

I am trying to dissolve base metals off of gold plated electronic scrap, and I am using HCl to dissolve some of the base metals. I pored in the HCl into a flask containing the scrap ( the contents of ...
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0answers
28 views

Does the concentration of a solution change when you add another solution to it? [closed]

Let’s say if I wanted to create a buffer. This buffer would consist of HF(aq) and it’s conjugate base, F-(aq). If I were to use 0.1 M HF and 0.28 M F- and add them to each other, would the ...
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2answers
296 views

What is the reaction equation for a mixture of trichloroethanoic acid and dimethylpropanoic acid?

Write an equation for the reaction you might expect to take place if trichloroethanoic acid, $\ce{Cl3CCO2H}$, $\mathrm{p}K_\mathrm{a} = 0.65$, were added to dimethylpropanoic acid, $\ce{(CH3)3CCO2H}$, ...
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2answers
52 views

How are CH3COOH molecules ionisied into H+ and CH3OO- [closed]

It's written in my chemistry book ,under weak acids, that the molecules of organic acids are partially ionised in water into ions. But I don't understand how molecules are ionised. I'm an ol ...
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2answers
368 views

Can we use (KBr + H2SO4) instead of (NaBr +H2SO4) in reaction with alcohol to generate alkyl bromide?

I have read somewhere that $\ce{H2SO4}$ is used to generate $\ce{HBr},$ and at the other place it is written that it is there to protonate the hydroxyl group. Which fact should I believe ?
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1answer
484 views

Back titration of excess HCl used for dissolving limestone

$15.0~\mathrm{mL}$ of $1.4~\mathrm{M}\ \ce{HCl}$ was mixed with $1.00~\mathrm{g}$ of limestone (impure $\ce{CaCO3}$) until all the solid had dissolved. The solution was then transferred to a conical ...
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2answers
39 views

How can I eliminate the harmful gas produced from the heating/manipulation of galvanized steel? [closed]

When welding on steel with a galvanized coating, hexavalent chromium is yielded from the chemical reaction. This gas is something that I would like to eliminate before I begin welding, possibly with ...
5
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1answer
2k views

Why is tetramethylammonium hydroxide a stronger base than tri- or dimethyl amine?

Of the following, which compound is the most basic?? $\ce{Me3N}$ $\ce{Me2NH}$ $\ce{Me4NOH}$ $\ce{NaOH}$ Between 1 and 2, 1 is more basic as the 3 methyl groups would produce a +I ...
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2answers
109 views

Strength of bases and acids

Is it possible that strong acids like $\ce{H2SO4}$ behave as weaker ones like $\ce{CH3COOH}$ when the concentration is really high and vice versa for weak acid? And the same question for bases. By ...
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3answers
8k views

Why is HCl a stronger acid than Acetic Acid?

Drawing the conjugate bases, Oxygen is more electronegative than Chlorine so negative charge on Oxygen is more stable than Chlorine, Thus My argument that Acetic Acid is more acidic. Also the O¯ ...
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0answers
68 views

Can Acids have pH of more than 7? [duplicate]

Consider a solution of $\text{HCl}$ with a concentration of $10^{-10}$ $\text{M}$. Now, if I find it's pH: $$\begin{aligned}\text{pH} &= -\log([\text{H}^+])\\ \text{pH} &= -\log(10^{-10}) = 10\...
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1answer
44 views

How to tell if an acid disassociate completely or partially? [closed]

what is the difference between and how can I tell which one is the stronger acid, base on the 2 equations?
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1answer
30 views

Why does Calcium (specifically Calcium Carbonate) inhibit the Citrate buffer system?

Is it because citrate chelates calcium and then is unable to react with other chemicals being added? If so can someone explain this reaction to me, or if not provide what the reason is? If anyone has ...
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1answer
46 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 ...
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1answer
29 views

What happens to concrete if you add lye to the mix?

What happens if you’re mixing concrete and you add some lye to it? Does it make it weaker, stronger or does nothing at all? I’m guessing concrete is basic so adding lye to it might expedite the ...
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1answer
51 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: $K_h = 5.6\times 10^{-10}$ ...
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2answers
485 views

Find the pH of an amphiprotic salt dissolved in water at room temperature

Let's say I have a polyprotic acid $\ce{H2A}$ with the following properties: $$ \begin{align} \ce{H2A &<=> HA- + H+} & K_1 &= 1\cdot 10^{-1}\\ \ce{HA- &<=> A^2-+ H+} & ...
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3answers
81 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 $...
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0answers
37 views

Why H3PO2 does not form acid salt? [closed]

Why $\ce{H3PO2}$ does not form an acid salt? I didn't understand the language.
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1answer
639 views

why are amines more water soluble than alcohol for similiar molecular weight?

kindly someone please explain the reason behind this behaviour despite the fact that oxygen is more electronegative and forms stronger hydrogen bond.
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1answer
38 views

Which is more basic among N-ethylpiperidin and 1-azabicyclooctane?

Shouldn't A be more basic than A because in B the conjugate base formed in B is more unstable as compared to A and because a bridge head nitrogen is formed In B which is comparatively unstable than ...
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0answers
36 views

Are all bases and acids salts? [duplicate]

Since all bases have hydroxide anions in them, and (a lot of) acids have hydrogen cations in them, aren’t most acids and bases salts as well? (When not dissolved in water)
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3answers
6k views

Reaction of concentrated nitric acid react with metallic lead?

Here is my work: Concentrated $\ce{HNO3}$ should first decompose into $\ce{NO2}$, $\ce{H2O}$ and $\ce{[O]}$. Nascent oxygen should combine with $\ce{Pb}$ to form $\ce{PbO}$. Now $\ce{PbO}$ should ...
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1answer
3k views

Order of lewis basic strength

My teacher told me that order of lewis basic strength is inversely proportional to electro negativity. Comparing between iodide ion and chloride ion, chloride ion is more electronegative than iodide ...
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1answer
135 views

How sure can we be about the structure of purine?

While answering the question Basicities of nitrogen atoms in purine, I noticed, that there might be a rapid interchange of the hydrogen bonded to the nitrogen atoms. I have found a crystal structure ...

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