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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6 views

How can I wet etch Nickel Chloride (NiCl/NiCl2) off a GaN sample

Apologies in advance for what may be a basic chemistry question - I'm asking from the point of view of microlithography. I have a Gallium Nitride sample which I have etched in a Ar/Cl plasma with a ...
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Find the acid dissociation constant given the Kw

A weak acid of initial concentration $\pu{0.2 M}$ with a strong base is titrated until complete neutralization. At the equivalence point the $\mathrm{pH}$ is $9.02.$ Calculate the acid dissociation ...
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46 views

Why don't conc HNO3 react with Al2O3,Cr2O3 and Fe3O4?

The reason for conc. $\ce{HNO3}$ not reacting with aluminum, chromium and iron was given as the formation of protective oxide layer. But the oxides of these metal are amphoteric($\ce{Al2O3,Cr2O3}$)/...
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Why doesn't base/acid reacting with water create a salt?

An acid/base nwutralization will create a salt + water. If one uses water itself as the acid or base, and have an acid/base neutralization, how come that doesn't create a salt? For example:$$ \ce{HCN(...
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if not the catalyst, can the rate of reaction be infinitely high when I increase the temperature

for example, I did an experiment before, I used enzyme and hydrogen peroxide, the rate of reaction will stop increasing since the enzyme will denature under an overly high temperature, I want to see ...
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Can acetic or hydrochloric or nitric acid have any effect on Glycine in an aqueous solution? [closed]

If I saturate water with Glycine at 100C and add pure Acetic Acid (in quantities equal to 5% of the volume of the solution) and leave it under reflux for a night, will the glycine be affected in any ...
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Are all ions bases/acids or their conjugate forms?

If one has a cation, is that always a base or a conjugate base? If one has an anion, is that always an acid or conjugate acid? If not, can you mention any of these ions? Also, if not every ion needs ...
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53 views

Why is H2O a weaker acid than acetylacetone? Shouldn't a hydrogen connected to an oxygen be more acidic than a hydrogen connected to a carbon atom? [closed]

I recently started studying chemistry after a long pause in my education so pardon me if it is a simple question. In the organic chemistry course I am taking, the professor told us that the first ...
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1answer
35 views

Why did my vinegar not create the traditional volcano?

At the weekend, my son and I tried the volcano experiment. You know the one: vinegar introduced to sodium bicarb (and a little red dye) within a conical "volcano". Not actually ours; photo ...
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Base/acid reaction -> alcohol amphoteric? why no pkb value?

I have a question concerning acid/base reactions. Is it true that an alcohol is a better base than water? My Professor listed the basicity (because we talked about E1/E2 and Sn1/Sn2 reactions) of the ...
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What is the equation for reaction between sodium citrate acidic buffer and sodium bicarbonate? [closed]

Trisodium citrate has a pH of 6.0 whilst the sodium bicarbonate I used was quite basic with a pH of 10.0±
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30 views

What concentration is phenolphthalein indicator ? 1% or 0.1%

I read some information about phenolphthalein indicator, some websites suggested phenolphthalein indicator of 1%, others mentioned phenolphthalein indicator of 0.1%. What is the difference of both of ...
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What is the formula for the reaction between aqueous sodium carbonate and trisodium citrate buffer [closed]

I reacted these two in an experiment. I understand that when sodium carbonate reacts with water it forms sodium hydroxide. So, is the OH- from the sodium hydroxide that reacts with the trisodium ...
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Why is [H2F+][SbF6-] the strongest Lewis acid

I have seen a similar question asked but there seems to be no answer rather a discussion on specifics. Wikipedia says that fluoroantimonic acid is the strongest conventional acid for liquids. The ...
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Neutralising weak acid solution using readilly accessible substances [closed]

What could be a cheap, cost effective way to consistantly neutralise large, cumulative amounts of a weak acid solution using readilly accessible substances?
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1answer
38 views

Why does the pH of a weak acid not increase by 1 when diluted by a factor of 10? [closed]

Strong acid pH increases by one unit when diluted by a factor of 10, but why do weak acids not?
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Identifying which lone pair is more basic?

In the the compound RCONH2 which lone pair is more basic? Is it the lone pairs on Oxygen atom or the lone pair on Nitrogen atom. I believe that as O is more electronegative than N, the lone pair on O ...
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Acid-Base Titration of ammonium dihydrogenphosphate?

How can I determine the concentration of ammonium dihydrogenphosphate solution? In this compound, the ammonium cation and the dihydrogen anion are both weak acids. I have a weak solution of this salt, ...
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Why does concentrated sulfuric acid have a strong affinity for water? [duplicate]

I have recently studied the laboratory preparation of hydrogen chloride gas, HCl, and the purification process involves the passage of the HCl has through concentrated sulfuric acid, H2SO4, to remove ...
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Preparation of ammonium acetate buffer for HPLC

Buffer solutions are typically prepared by dissolving an appropriate salt in water and then adjusting the $\mathrm{pH}$ to the desired position by addition of the conjugate acid or base. For example, ...
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35 views

Finding the best indicator for titration of a weak base and strong acid (NH3 + HCl) with only a Ka value

The best indicator to use in a standard titration of aqueous $\ce{NH3}$ $(K_\mathrm{a}(\ce{NH4+}) = \pu{5.7E-10})$ with an $\ce{HCl}$ is $$ \begin{array}{llc} \hline & \text{Indicator} & \...
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What are the compounds in oxygen and carbon dioxide indicator solutions that gives their color?

My brother had some leftover oxygen and carbon dioxide indicator solution for one of his take-home experiments from school, so he let me have them. I want to use them for an experiment and write out ...
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Where can I find literature values for standard molar enthalpies of neutralization?

I'm looking for enthalpy of neutralization literature values for inorganic weak acids. NIST, PubChem, etc. don't list them. Is there somewhere else I should look?
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Comparing basic strengths between pyridine and 1,2-dihydropyrazine

Compare the basic strengths of above two compounds. In the first compound (1,2-dihydropyrazine), the lone pair of one N will participate in resonance but the lone pair of other N will not, similarly ...
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CaCl2 and Citric Acid react /w metal pot

I'm building a dehumidifier based on $\ce{CaCl2}$-solution as descant, which is to be regenerated by heating and evaporation. I thought it would be a good idea to add some citric acid to combat chalk-...
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Is sodium aquo complex a Brönsted-Lowry acid?

I know that according to Brönsted-Lowry theory, a base is a proton acceptor while an acid is a proton donor. Also, the acid-base pair that differs by a single proton is a conjugate pair. If this is ...
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62 views

How to find the moles of a salt added to a weak base, given ph

I would really appreciate some help with how to approach this: I'm given that: Methylamine (CH3NH2) is a weak base used in the manufacture of pesticides. Taking into account that the degree of ...
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1answer
54 views

Reaction between barium peroxide and hypochlorous acid

When $\ce{BaO2}$ reacts with $\ce{HClO},$ the question tells us that that oxygen, barium chloride and one other product is formed. The equation I came up with is $$\ce{BaO2 + 2 HClO -> BaCl2 + 2 O2 ...
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88 views

Isn't water a Lewis base in the ammonia–water reaction?

Exactly one of these statements is false. Which one? (a) When ammonia dissolves in water, the latter behaves as a Lewis base. (b) The conjugate acid of $\ce{H-}$ is $\ce{H2}.$ (c) Boric acid is a ...
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32 views

Number of lone pairs as a measure of basicity [closed]

$\underline{\text{Consider the following question:}}$ The first difference I noticed in these compounds was the large number of oxygen atoms in (IV). This definitely means that there is a larger ...
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Double Equivalence Point Calculations for Oxalic Acid [closed]

Question: Oxalic Acid, H2C2O4 has two pKa values, 1.25 and 4.27. A 0.100 M solution of oxalic acid was titrated with a 0.100 M solution of HaOH. What is the pH at the second equivalence point? a) 1.23 ...
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Does carbonation permanently increase the acidity of soda water?

If you carbonate water, and then expose the resulting soda water to the atmosphere and wait until it goes completely flat, will the (former) soda water end up more acidic in final equilibrium than ...
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60 views

What's the chemical reaction between coffee and sodium bicarbonate? [closed]

Every morning I put sodium bicarbonate into my coffee and I was wondering what chemical reaction this produces and what are the chemicals produced at the end. I cannot find an answer to this question ...
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57 views

In the pH system of acids and bases, are there 10^-7 loose ions per liter (at pH of 7) or per mole of solvent? (Or per mole of total substance?)

Most places tell me that the number on the pH scale tells you the number of dissociated ions, in moles, per liter of substance. But, Wikipedia's article pH says this....: ... For a commonplace ...
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Difficulty in understanding ionisation of sulphuric acid [closed]

$\ce{H2SO4}$ when added to water. $\ce{H2SO4 + 2 H2O -> SO4^2- + 2 H3O+}$ My sir explained me these reaction as $\ce{H}$ will give $\ce{2 H^+}$ ions to the base $\ce{H2O}$.So why does it not become ...
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30 views

Is there a notion of generalized acidity for lithium ions?

From my understanding, the basic notions of acidity can be explained by considering a cup of pure water, and then adding a substance to it which creates either free $\ce{H+}$, or free $\ce{H3O+}$ and $...
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45 views

Why are some weak acid equilibrium approximations invalid in very dilute solutions?

Using two approximations for the dissociation of a weak acid, we can write $$K_\mathrm{a}= \frac{[\ce{H+(aq)}]^2}{[\ce{HA(aq)}]}$$ One of these two approximations we use is that the concentration of ...
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58 views

Is there an “off the shelf” way to make magnesium ascorbate? [closed]

I make my own sodium ascorbate with ascorbic acid and sodium bicarb. It's easy, I get the vitamin c off ebay and the baking soda from the store. Is there a similar way to make magnesium ascorbate: ...
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pKa = pH for strong acid — strong base?

I have learnt that for a weak acid — strong base titration, $\mathrm{p}K_\mathrm{a} = \mathrm{pH}$ at the half equivalence point. However, the same conclusion is not drawn when discussing strong acid —...
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When multiple sources give the content of an ingredient my an unqualified percentage, can I safely assume this is by weight? Or; it's not a wart

I am trying to make a simple scented shampoo and body soap for my own use and for Christmas gifts. I statr with a base of 32 oz – (a bit under a kg) of a mild commercial castille soap (Dr. Bronner’s ...
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71 views

Why does a proton react with water to form hydronium ion and why does that ion has an overall positive charge? [closed]

Take this is an example: $$\ce{HCl(aq) -> H^+(aq) + Cl^-(aq)}$$ and $$\ce{HCl(aq) + H2O -> H3O+ + Cl^-(aq)}$$ Clearly the proton latches on to the water molecule but why? Also, why does the ...
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Why is the gradient of the curve of a strong base titrated with strong acid small up until equivalence?

I understand the cause of the sharp decrease in pH upon reaching the equivalence point, but I don't understand why addition of relatively large amounts of the strong acid would be accompanied with ...
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56 views

Effect of dilution on weak acids pH [closed]

My textbook has a question which says what would happen to the pH of a weak acid if it is diluted with water. The answer is its pH would decrease. My teacher’s argument is that it would indeed ...
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96 views

Why is dilution exothermic?

The breaking of bonds usually absorbs energy and forming bonds usually releases energy. Then, why is the dilution of acids and bases exothermic?
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29 views

CO2 + High humidity = transperent substance?

First I want to point out that I am not a chemist, sorry for bad description. I have CO2 incubator. CO2 concentration is 10-20% and the humidity level is around 90%. I was using a humidity sensor to ...
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76 views

What are the applications of tetraxenonogold(II)?

I recently stumbled upon a pretty interesting chemical: tetraxenonogold(II) $\ce{AuXe4^2+}.$ Basically, an atom of gold with four xenons around. It is a product of a superacid reaction and it is ...
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23 views

Removing ashes of 3d printing resin

I'm not a chemist so excuse me if my question will bite your eye or ear. A resin 3d printing uses polymers that cure under exposure to UV light. There is a special sort of 3d printing resins made for ...
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1answer
140 views

What is the difference between these two formulas for pH of weak acids?

In the German Wikipedia article on $\mathrm{pH}$, I found the following formula for calculating the $\mathrm{pH}$ of weak acids (which are there defined of having $4.5 < \mathrm{p}K_\mathrm{a} < ...
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95 views

Why do we not using concentrated HCl and zinc reaction to prepare hydrogen?

First apologize for this kind silly question.One of my student ask me this question but I was unable to get a perfect answer from internet.Generally dilute HCl and impure zinc are using for hydrogen ...
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1answer
61 views

Order of Lewis acid character among sulfur hexafluoride, sulfur tetrafluoride and tetrachloromethane

Problem Compare the order of Lewis acid character of $\ce{SF6},$ $\ce{SF4}$ and $\ce{CCl4}.$ My attempt Oxidation state of $\ce{S}$ in $\ce{SF6}$ is $+6,$ so it is very electrophilic. $\ce{S}$ has a ...

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