An acid is either a proton donor, or an electron-pair acceptor. A base is either a proton acceptor, or an electron-pair donor. In aqueous solution, acids have a pH less than 7 and bases have a pH greater than 7.

learn more… | top users | synonyms (2)

0
votes
1answer
27 views

Aqueous vs. Solid

I've been having a conceptual struggle with these two states for a while now, and I'd like to get it cleared up. A compound AB dissolves in water. $$\ce{AB(s) + H2O <-> A+(aq) + B-(aq) + ...
1
vote
1answer
25 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 ...
0
votes
1answer
28 views

How to identify a substance acting as an acid

For question ii, it asks to state a reaction showing $\ce{H2SO4}$ acid acting as an acid. What does it mean acting as an acid? Donating a proton? Very confused as to what to look for. The answer ...
2
votes
0answers
59 views

What is the pKa of the oxonium / hydronium / H3O+ ion?

Although the wikipedia page on Hydronium indicates a pKa of -1.74, I noticed in the discussion of this page that the subject seems debated (cf. http://en.wikipedia.org/wiki/Talk:Hydronium#pKa.3F) ...
0
votes
1answer
47 views

MaVa = MbVb - Limitations and Uses

We know that for strong acids with a $1:1$ mole ratio between all particles involved are suitable for use with the aforementioned formula for titration problems. I want to know the limits on this ...
2
votes
1answer
45 views

Why do only certain acids disassociate in water?

I understand that most acids are weak acids, i.e. they do not fully disassociate in solution. However, certain acids, such as $\ce{H2SO4}$, do. I have been unable to find out what the defining ...
1
vote
2answers
57 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 ...
2
votes
2answers
40 views

Chemical Formulas of Acids and Bases [duplicate]

How can we identify bases and acids by their chemical formulas? Take for example this reaction. I know that HNO3 is an acid and KOH is a base, but if I didn't know that how would I be able to ...
2
votes
2answers
116 views

Why does having equivalent resonating structure give more stability?

If we take a phenolate ion ($\ce{C6H5O-}$) and an acetate ion ($\ce{CH3COO-}$) which one would be more stable? Although the Phenolate ion has more(4) resonating structure compared to acetate ion(2), ...
1
vote
2answers
42 views

Acid chlorides… are they really acidic?

If I get a pure solution of an acid chloride and place a pH meter into the liquid, will I get a reading of pH 7? When I add water to it, I know $HCl$ gas will form but will this gas dissolve in water ...
0
votes
0answers
77 views

pH of amino acid solutions

Hi may someone help me with this question A glycine ($\ce{NH2CH2COOH}$) is a standard amino acid with two $\text{p}K_{a}$ ($\text{p}K_{1}=2.0$ for $\ce{-COOH}$ and $\text{p}K_{2}=10.0$ for ...
0
votes
2answers
66 views

When we dilute a weak acid, pH increases but dissociation increases

When water is added to a weak acid like ethanoic aicd, number of ethanoic acid molecules that dissociate increases however, pH increases (less acidic)... but why?
1
vote
1answer
169 views

Calculate the moles of acid and conjugate base needed

I tried to look up the way to do this question but I could not find any helpful information in order to help me solve this question. Q: Using the following salts listed below, calculate the moles of ...
2
votes
1answer
31 views

Volume required to dilute solution for a pH change

A 100 ml solution of NaOH has a pH of 13. What volume of water, in mL must be added to change the pH to 11? My Steps: So, begin by calculating conc. of [OH-] for pH 13. Then find the moles by ...
0
votes
1answer
25 views

Strength identification in conjugate acid-base pairing

I'm a student in highschool AP chemistry. I'm confused about a certain problem in my chem textbook. In summary, I am given a species and asked to identify its basicity as strong, weak, or negligible. ...
2
votes
3answers
93 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 ...
2
votes
1answer
422 views

Why is phenolphthalein an appropriate indicator for titration of a strong acid with a strong base?

Please explain based on the pH at the equivalence point and the transition range for phenolphthalein. Thanks for the help.
0
votes
1answer
89 views

Write an equation to show how HC2O4− can act as an acid with HS− acting as a base [closed]

Write an equation to show how $\ce{HC2O4^{−}}$ can act as an acid with $\ce{HS^{−}}$ acting as a base. Express your answer as a chemical equation. Identify all of the phases in your answer.
2
votes
1answer
228 views

Can someone please explain buffers to me?

This is what I understand so far: The concept of a buffer is to minimize any swings in pH. In order to do this you need to create a solution with both acidic and basic compounds. To create one, you ...
2
votes
2answers
42 views

How do you have pKa for a base?

The $pK_a$ is the $-\log_{10}$ of the $k_a$ value for the disassociation of an acid. So how do you get a $pK_a$ value for a base? The base produces no hydrogen ions so can't you only have a $pK_b$?
3
votes
1answer
62 views

A simple high school chemistry question

$60$% of $\ce{NaOH}$ included in a mixture of $\ce{NaOH}$ and $\ce{Ba(OH)2}$. $2.0$ g of this mixture is dissolve in water and diluted up to $500$cm$^3$. What is the volume of $0.1$ ...
0
votes
1answer
47 views

Is alcohol lewis base or bronsted base?

I know that Lewis' concept of acid base deals in terms of electrons and Bronsted in terms of $\ce{H+}$ and base which can provide electrons or $\ce{OH-}$. If I am wrong (partially or fully) please ...
4
votes
2answers
203 views

reason for the stronger acidic property of phenol than alcohol

"In phenol, pulling the $p_z$ electrons from the oxygen atom into the ring causes the hydrogen atom to be more partially positive than it is in aliphatic alcohols. This means it is much more easily ...
1
vote
1answer
50 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, $\ce{NH4+}$ ...
5
votes
3answers
461 views

How can I make an acidic pen to burn paper on writing on it?

If I have a pen with refillable ink, can I just pour in concentrated Hydrochloric acid or concentrated sulphuric acid in the ink chamber to make it an acidic pen? Would it be better to use the acid ...
4
votes
1answer
366 views

Rate and mechanism of the reaction of Mg and HCl

In the reaction between hydrochloric acid and Magnesium the overall reaction is: $$\ce{Mg + 2HCl -> MgCl2 + H2}$$ My proposed mechanism of reaction is that $\ce{HCl}$ dissociates in $\ce{H2O}$ ...
1
vote
1answer
126 views

NaH2PO4 in water : Acid/base?

Will $\ce{NaH2PO4}$ react as as an acid or a base if you make it react with water? I got stuck here. I can figure out the reaction: $\ce{NaH2PO4 + H2O -> Na^{+} + H2PO4^{-} + H2O}$ But when I ...
5
votes
0answers
46 views

Proton transfer equilibrium in bisulphite adducts

In the addition of $\ce{NaHSO3}$ to aldehydes and methyl ketones (higher ketones do not respond well to this reaction), crystalline addition products are formed. An $\ce{-SO3H}$ and an $\ce{-OH}$ ...
5
votes
2answers
462 views

How to separate HCl and NaOH from salt and water solution?

I mean, how can we reverse the neutralization reaction of HCl and NaOH to get back HCl and NaOH. I want to extract HCl and NaOH from a mixture of common salt and distilled water in equal proportions ...
5
votes
1answer
114 views

Why does HNO3 not give off H2 when reacting with Cu?

A dilute solution of which acid is most likely to produce a reduction product other than $\ce{H_{2}}$ when it reacts with a metal? (A) $\ce{HF}$ (B) $\ce{HCl}$ (C) $\ce{HNO3} $ ...
1
vote
1answer
71 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
votes
1answer
46 views

$\ce{NO2-}+\ce{H2O}$

I'm reviewing for my AP Chem acid-base equilibrium test, and I'm working problems out of the book, I have a problem that asks: "Predict the products of the following acid-base reactions, and predict ...
4
votes
1answer
61 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}= ...
0
votes
0answers
22 views

pH of acetic and citric acid [duplicate]

How do I calculate pH of acetic and citric acid? I know the formulas are $\ce{CH3COOH}$ and $\ce{C6H8O7}$, and that $p\text H = -\log(\ce{H3O+})$ but I'm not sure what to do?
0
votes
1answer
55 views

How to determine the reaction of a strong electrolyte?

I'm told the $\ce{KMnO4}$ is a strong electrolyte. How can I figure out how the reaction looks like?
1
vote
2answers
261 views

What are the products of the dissociation of NaHCO3 in water? What is the relative pH of the solution?

I had a recent question on a test that asked what the products would be if Sodium Hydrogen Carbonate were dissolved in water. I had a few candidate answers $\ce{NaHCO3}\rightarrow ...
1
vote
1answer
117 views

Reaction of sodium dihydrogen phosphate and ammonium chloride

I have a homework question that says "Write an equation when $\ce{NaH2PO4}$ and $\ce{NH4Cl}$ are mixed." I assume that this is an acid base neutralization and will probably also give a salt due to the ...
2
votes
1answer
38 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 ...
3
votes
1answer
142 views

Why does acetylene, having acidic proton, not react with strong bases like $\ce {NaOH}$ and $\ce {KOH}$?

We know that the $\ce C$ atom in acetylene ($\ce {H-C\bond{#}C-H}$) is $sp$ hybridised and so is more electronegative than alkenes or alkanes. This electronegativity makes the $\ce H$ an acidic one. ...
1
vote
1answer
74 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:- ...
2
votes
1answer
112 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 ...
1
vote
2answers
57 views

Does HCL kill algae?

I live in the tropics, and have a water tank that sits in the sun, forming algae. Every year, I need to scrub the thing out. The plumber I've hired for the job wants to flush my water pipes with HCl ...
2
votes
1answer
91 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 ...
5
votes
3answers
738 views

the reason behind the steep rise in pH in the acid base titration curve

Most books refer to a steep rise in pH when a titration reaches the equivalence point. However, I do not understand why... I mean I am adding the same drops of acid to the alkali but just as I near ...
1
vote
1answer
250 views

Shouldn't the pH at the equivalence point always be 7?

I learned in class that the equivalence point in an acid-base titration is reached when the solution contains equal number of moles of $\ce{OH-}$ and $\ce{H+}$ ions. However, in a weak acid and strong ...
2
votes
3answers
112 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. ...
1
vote
0answers
41 views

Can F2/HF be separated using acid/base solutions in series?

I am trying to verify the results of EPA method 26A (http://www.epa.gov/ttnemc01/promgate/m-26a.pdf). The Method claims to be able to separate and quantify a mixed halogen/halide gas stream. Although ...
1
vote
2answers
519 views

What is the pKa Range for weak acids and bases?

Am I correct in assuming that the following is true? $pK_a < 3$ is for a strong acid $3 < pK_a < 7$ is for a weak acid $7 < pK_a < 11$ is for a weak base $pK_a > 11$ is for a ...
1
vote
0answers
35 views

What's the reaction order of a strong acid and a strong base/carbonate salt/metal /weak base and why?

If a strong base (e.g.$\ce{NaOH}$), a weak base ($\ce{NH3}$.$\ce{H2O}$), a reactive metal (e.g. $\ce{Mg}$) and a carbonate salt (e.g.$\ce{Na2CO3}$) are contained by a flask, what is the order of ...
1
vote
0answers
79 views

Does the number of H+ ions in solution go up on dilution of a weak acid?

In my textbook, a footnote says: In case of weak acids, on dilution the total number of $H^{+}$ ions in solution increases because dissociation of the weak acid increases This didn't make sense ...