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
121 views

Formation Constants; Lewis Acidity

I still distinctly remember reading about how Lewis acidity/basicity was characterized using kinetics. The reason given was that because formation constants are so large, these reactions are not ...
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16k views

'Hard' soap vs. 'Soft' soap: Why do they work this way?

In school, we did an experiment using fat and $\ce{KOH}$ to create 'soft' soap. Afterwards, we added $\ce{NaOH}$ to change it into 'hard' soap. I read on multiple places on the internet that the ...
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277 views

Any possible additives to a drain cleaner I use as a source of NaOH?

It is in pellets. And the box says main ingredient $\ce{NaOH}$ at least $30\%$ (I hope it's more). The box also says "aluminium catalyst". My goal was to take these pellets and dissolve them in water ...
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1answer
148 views

Conversion of CO2 to methane

Suppose one could generate an enzyme with arbitrary conditions at the active site. What conditions would then be necessary to cause carbon from dissolved $\ce{CO2}$ in low $pH$ water to combine with ...
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1answer
1k views

How to calculate the pH of a buffered solution with Henderson Hasselbalch?

Lets say you have a buffered solution containing $0.50~\mathrm{M}$ acetic acid ($K_a = 1.8 \cdot 10^{-5}$) and $0.50~\mathrm{M}$ sodium acetate, and you want to calculate the $\mathrm{p}\ce{H}$ of ...
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2answers
525 views

Molality and dissociation

For $\ce{HCl(aq) -> H^{+}(aq) + Cl^{-}(aq)}$, if $\ce{HCl}$ has a concentration of 1 molar then $\ce{H+}$ and $\ce{Cl-}$ also have 1 molar. But for $\ce{HF(aq) <=> H^{+}(aq) + F^{-}(aq)}$, if ...
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1answer
951 views

Differentiating between Titration, Buffer, diluted buffer, Deionized H₂O

I had a chemistry lab where we had to titrate three solutions with HCl, a buffer, a diluted buffer and deionized water. My partner and I didn't label the charts we made, so now I have to figure out ...
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3answers
2k views

Why does an acid exist when dissolved in water?

Acid is a substance that releases $\ce{H+}$ ions when mixed with water But if it releases $\ce{H+}$ ions the acid will ultimately not exist. For e.g we take the acid $\ce{H2SO4}$. If we add water ...
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2answers
102 views

Reconciling the units of pH calculation

As part of a simulation I am developing I have an acid in aqueous solution represented as a concentration field of mass density (units g/L) at various points in ...
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0answers
43 views

ice cream float - what causes it? [duplicate]

When you mix ice cream and a soft drink (like coke,) a reaction happens that creates a thick foam. I am assuming the foam id composed of carbon dioxide gas and milk curd, which is produced by the ...
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1answer
246 views

Which acids are created by the combination of a gas and water?

Which acids are created by the combination of a gas and water? I know that carbonic acid is created by combining carbon dioxide and water, but are there others? Is there a specific name for this ...
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1answer
6k views

Why is Aluminium Chloride a Lewis Acid if it's an ionic compound?

In my textbook it says in the reaction $\ce{AlCl3 + Cl- -> AlCl4-}$, Aluminium Chloride ($\ce{AlCl3}$) has six valence electrons and accepts a lone pair from $\ce{Cl-}$, but wouldn't that mean the ...
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1answer
3k views

Separation of Binary mixture?

I will be given a binary mixture containing two unknown compounds(the mixture could be either liquid or solid- I don't know yet). The plan of the experiment is to identify the two compounds. So my ...
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1answer
908 views

Homoassociation and Acid Strength

I understand that the strength of HF differs significantly depending on the concentration. I understand the basic theory behind this - homoassociation - and stabilization of the highly negative charge ...
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2answers
2k views

NCl₃ + H₂O → NH₃ + HOCl , the resulting solution is acidic, basic or neutral?

When $\ce{NCl3}$ is dissolved in water, $\ce{NH3}$ and $\ce{HOCl}$ is formed. Can you please explain me whether formed solution is acid or basic or neutral? thank you!
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1answer
955 views

Activation Energy in Acid/Base reactions

For simple acid/base reactions - i.e. those involving inorganic compounds - does activation energy ever play in reactions? Or can we ignore kinetics entirely and just consider thermodynamic factors ...
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1answer
93 views

Since aqueous acids release Hydrogen cations into the solution, will an electric current create Hydrogen gas?

I was wondering that since acids dissociate in water to make a lot of $\ce{H+}$ cations. Is it possible that introducing a supply of electrons via an electric current, would create $\ce{H2}$ gas?
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3answers
8k views

Why is a buffer solution most effective when concentrations of salt and acid are the same?

Why does a buffer work most effectively when the concentration of salt and acid is 1:1?
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1answer
971 views

Esterification and dehydration synthesis

I know there are many more terms out there like polymerization, condensation, etc. But the important thing is whether they can be differentiated or not. In Esterification, which I just learned, needs ...
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3answers
3k views

Inductive effect

In my teacher's power-point states that we must consider that inductive effect in $CH_{3}COOH$ exists because of the electron deficiency in $C$ (partial positive charge $\delta^{+}$) as a result of ...
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2answers
4k views

Acidity of aldehydes

Which is more acidic between methanal ($\ce{HCHO}$) and ethanal ($\ce{CH3CHO}$). Please explain using General organic chemistry basic concepts. My Effort: I saw the stability of the conjugate base. ...
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2answers
86 views

What's the Acid Ionization Constant of the Hydrogen Proton?

What is the $\ce{K_{a}}$ value for $\ce{H^+}$. I understand that the hydrogen proton doesn't stick around in solution by itself for very long. Nonetheless, does it have a $\ce{K_{a}}$ value? Can it ...
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1answer
110 views

Balancing Redox Equations

I was taught to balance redox equations with acid/base considerations. Instead of arbitrarily adding $\ce{H^+}$ and $\ce{HO^-}$ ions and memorizing separate rules for acidic and basic solutions, I was ...
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2answers
3k views

Hydrolysis of ammonium cloride

As we all know ammonium chloride is a acid. And what explains this is its salt hydrolysis. It breaks down into ammonium and chloride ions. Ammonium react with water to produce hydronium or hydrogen ...
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1answer
1k views

Identifying Nucleophiles and Electrophiles

Are all polar molecules both nucleophilic and electrophilic, depending on which atom you are talking about? Take water for example. Oxygen bears the partial negative charge. Oxygen is nucleophilic. ...
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1answer
190 views

Strongest B/L Acid Which Can Exist (Leveling Effect)

Got a few issues with this: Here is the Lewis Structure: As we can see, we have five lone pairs on which a hydrogen proton can land and form the solvent's conjugate acid. Let's consider them left ...
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1answer
418 views

Properties of Polyprotic acids?

I have a graph of a titration of a weak polyprotic acid with a strong base. I graphed $p\ce H$ versus amount of strong base added. Now since the acid is polyprotic, how do I determine which ...
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1answer
1k views

What are the factors that affect the corrosiveness of an acid?

Acids are usually corrosive but what determines this? Is it the concentration of the acid or strength of the acid ($K_a$ value)?
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1answer
510 views

Thymolphthalein solubility

I already know that thymolphthalein is soluble in alcohols, very alkaline aqueous solutions, acetone, and propylene glycol methyl ether. My questions are what other solvents dissolve thymolphthalein, ...
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1answer
25k views

Predicting the pH of a weak acid and weak base solution

I know that it is possible to predict whether combinations of acids and bases will be acidic, basic, or neutral: weak acid (WA) and strong base (SB) reacts basic strong acid (SA) and and weak base (...
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1answer
69 views

Explain why the acidification of solution can lead to separation of ions such as Fe2+ and Zn2+ from aq solution

Given the $K_{sp}(\ce{ZnS})= 2.5\cdot10^{-22}$ and the $K_{sp}(\ce{FeS})= 3.7\cdot10^{-19}$, why would $\ce{Fe^{2+}}$ ions remain in the solution but not $\ce{Zn^{2+}}$ with the acidification of the ...
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2answers
143 views

Carbon dioxide in lime ground

Is storing carbon dioxide in limestone a good idea? Wouldn't that lead to a reaction like $\mathrm{C}\mathrm{O}_2 + \mathrm{H}_2\mathrm{O}\to {\mathrm{C}\mathrm{O}_3}^{-2} + 2\mathrm{H}^+$ And then ...
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2answers
102 views

How can you tell how much actually reacted in an acid base reaction

If you facilitate a weak acid base reaction. i.e. $\ce{NaOH + H2SO4}$. All of it may not react and the solutions will not neutralize. How can you determine how much actually reacted?
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3answers
5k views

Halogen Oxyacid Trend (acid strength)

Why is $\ce{HClO4}$ more acidic than $\ce{HBrO4}$? But $\ce{HCl}$ is less acidic than $\ce{HBr}$? What determines the acidity? Is it the concentration of $\ce{H+}$? If so, how do these trends develop ...
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3answers
965 views

Anthocyanins as pH-indicators: stop the titration at red, purple or blue?

If you titrate some hydrogen bromide solution (0.1 M) to some sodium hydroxide in order to determine the exact concentration of hydrogen bromide (0.1 M), and you use anthocyanins as a pH indicator. ...
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1answer
11k views

How do you calculate the total heat capacity of a reaction

I need help with this one homework question: I am combining $100\,\text{mL}$ of $0.5~\text{M}~\ce{HCl}$ and $100~\text{mL}$ of $0.5~\text{M}~\ce{NaOH}$ to obtain $200~\text{mL}$ of $0.25~\text{M}~\...
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1answer
258 views

Conjugate acids and bases

Consider the reaction $\ce{NH3 + H2O -> NH4+ + OH-}$ Here, $\ce{NH3}$ is a weak base, and thus $\ce{H2O}$ becomes a weak acid. Thus, shouldn't its conjugate be a strong acid? However, $\ce{NH4+}$ ...
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1answer
170 views

How to determine the reaction of a strong electrolyte? [closed]

I'm told the $\ce{KMnO4}$ is a strong electrolyte. How can I figure out how the reaction looks like?
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1answer
6k views

Is acetate a weak base due to its resonance structure?

I just read that acetic acid is an exception to the general idea that the conjugate base to a weak acid is a strong base. The example says that the conjugate base of a weak acid will only be strong ...
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1answer
2k views

The significance of the dissociation constant of an indicator

In the chapter acid-base, I learned about indicators and how they are actually weak acids. This is the equation given in our book: $\ce{HIn + H_2O <=> H_3O^+ + In^-}$ $K_{in}= \left(\frac{[\...
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1answer
82 views

Figuring out the concentration of weak polyprotic acids in presence of strong acid

We have a $\rm{0.1 \ M}$ solution of $\rm{H_2S}$ with a $\rm{0.1 \ M}$ solution of $\rm{HCl}$. We need to figure out the concentration of $\rm{S^{2-}}$ ions at equilibrium. $$\rm{H_2S \...
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1answer
1k views

Calculating approximate pH of polyprotic acids

When I took up ionic equilibria and titrations after a long break, I found it hard to solve the questions regarding pH calculations of polyprotic acds. Consider these two questions as examples:- ...
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1answer
4k views

How does iron rust in basic conditions?

I performed an experiment about the corrosion of iron. I used acid and base in the experiment. I understand that the acid speeds up the corrosion of iron. But I don't understand why the base also ...
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1answer
2k views

Buffers calculating amounts of acid & base

Quick run down, I was given pH of buffer 4.5 and then pKa of acid 4.79 I then had to work out volume of acid and volume of base using $\text{pH=pKa}+\log_{10}{\left(\dfrac{[\ce{A-}]}{[\ce{HA}]}\right)}...
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1answer
2k views

Corrosion of Aluminum by Baking soda

An aqueous solution of sodium hydrogen carbonate corrodes aluminum foil quite readily. How do you explain this?
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99 views

What are the properties of various solutions at pH <2 that may cause injuries?

For example, why do some solutions not cause any injuries at pH 2 while HCl does?
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1k views

Perfluorobutanesulfonic acid (PFBS) Safety and Toxicity

I was wondering if anyone had any experience with PFBS or PFOS (perflurooctane sulfonic acid)? I am thinking about trying to purchase some of these fluorosurfactants in bulk in order to (hopefully) ...
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1answer
15k views

Calculating the pH of a solution of Ca(OH)2

A solution prepared by dissolving $2.8 g$ of lime, $\ce{CaO}$ in enough water to make $1.00 l$ of lime water ($\ce{Ca(OH)_{2(aq)}}$). If solubility of $\ce{Ca(OH)2}$ in water is $1.48 g$. The $p\ce H$ ...
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1answer
111 views

How to Understand Concentrations Measurement

I was helping out in my beginner's chemistry class today, as I'm a "lab assistant" of sorts, and was reading on a bottle of HCl: 1M. I'm assuming that is the concentration of how much hydrocloric acid ...
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1answer
2k views

How to estimate pH?

How you you calculate/estimate the pH of a solution with 3 components all of different pHs? Is there a paper describing this? For example: 0.1M Buffer PCTP at pH 9.5 1.6M Sodium Dihydrogen Phosphate ...