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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2answers
419 views

What is the pH of HCl solution at $10^{-8}$M? [duplicate]

After using the negative logarithmic value of $\ce{H^+}$ ion concentration, I get a value of pH that results in base. Can you please help me? Thank you in advance
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1answer
406 views

Why carboxylic group gets protonated preferantially on carbonyl oxygen?

When carboxylic group gets protonated, by strong acid, proton binds rather to carbonyl oxygen, then to hydroxyl. Is that really true? Or maybe it's a case of kinetic vs thermodynamic stability?
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1answer
1k views

Calculating pH of solution of phosphoric acid and ammonia

What is the $\ce{pH}$ of the solution created when $\ce{50ml}$ of $\ce{0.2M}$ $\ce{H3PO4}$ is mixed with $\ce{50ml}$ of $\ce{0.4M}$ $\ce{NH3}$? This problem can be approached rigorously. That's what ...
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1answer
2k views

Salt hydrolysis or buffer solution [closed]

Whenever there a question comes to find the pH of the given solution, I always gets confused to identify the solution if it is a buffer solution or whether it will undergo salt hydrolysis . Can ...
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1answer
70 views

Is neutralized and dried suphuric acid still a hazard? Is it still acidic to touch? [closed]

I mistakenly put a sulfuric acid drain cleaner in my bathroom sink. Some of it spilled into the bathroom in my basement. I cleaned it up using baking soda, but I'm concerned if I missed any, whether ...
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1answer
49 views

Why do we need to use oxidation number in order to balance a complex chemical reaction easily in an acidic or alkaline medium? [closed]

I have been trying to balance this chemical reaction in an "acidic" medium without using oxidation number or ion electron method: [$\ce{Fe^2+ + Cr2O7^2- -> Cr^3+ + Fe^3+}$]. Though I can balance ...
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2answers
58 views

Why is the hydroxide ion not considered to be amphoteric [closed]

Why is the hydroxide ion not considered to be amphoteric. Why is $$\ce{2OH- <<=> H2O + O^{2-} }$$ not considered ?? Even though the equilibrium would mostly lie towards the left but still ...
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2answers
61 views

Finding the pH of the solution

In this video, at 3:30 min professor solves two equations $$\ce{H2O —> H+ + OH-}$$ and $$ \ce{HCl —> H+ + Cl-}$$ and deduces $[\ce{H+}] = [\ce{Cl-}] +[\ce{OH-}]$. How come this happen from ...
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1answer
27 views

Calculating the pH of Strong Acid Solutions [closed]

Calculate the $\mathrm{pH}$ of a $\pu{1.5e–11 M}$ solution of $\ce{HCl}.$ How is the $\mathrm{pH}~7?$
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4answers
2k views

Titration of Na2CO3 against HCl

$\pu{25 mL}$ of $\pu{0.125 M}$ $\ce{Na2CO3}$ is titrated with $\pu{0.100 M}$ $\ce{HCl}$. Given that $K_\mathrm{a1} = 4.3\times 10^{-7}$ and $K_\mathrm{a2} = 4.8\times10^{-11}$ for the diprotic acid $\...
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1answer
78 views

Why does Ca(CH3CH2CH2COO)2 dissolve in HCl and not in NaOH? [closed]

I do not understand why a strong base, such as NaOH would not dissolve a solid such as this. There would be a double displacement in which you form Ca(OH)2 and NaCH3CH2COO (aq). Why would HCl ...
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1answer
43 views

What is the reaction mechanism between a basic oxide and an acid?

For instance in $$\ce{ Li2O (s) + 2HCl (aq) -> 2LiCl (aq) + H2O (l)}$$ I am wondering why the $\ce{Cl}$ displaces $\ce{Li}$ .I figure that oxygen is negatively charged as it pulls the electron from ...
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1answer
280 views

Why does ammonium chloride form white crystals? [closed]

Why does ammonium chloride ($\ce{NH4Cl}$) form white crystals on top of a test tube when heated?
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1answer
160 views

How do we know that a matter is acidic or basic without knowing their $pH$ value? [duplicate]

There are too many examples for acidic matters as seen below. $$HCI \tag {1}$$ $$HNO_3 \tag {2}$$ $$H_2SO_4 \tag {3}$$ And the examples for basic matters $$NH_3 \tag {4}$$ $$NaOH \tag {5}$$ ...
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2answers
75 views

What do we call ions without basic and acidic properties

According to Brønsted theory, Acids are substances (molecules and ions) donating $\ce{H+}$ Bases are substances (molecules and ions) receiving $\ce{H+}$ I've been trying to find a complete Brønsted-...
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1answer
82 views

How does this oxazolone behave as an acid?

how can you explain the increased acidity (pka around 14) of this oxazolone compared to a standard cyclic amide/lactam)?
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1answer
62 views

Conditions for the reduction of dichromate by manganese(II) to chromium(III) [closed]

The unbalanced redox reaction $$\ce{Mn^2+ + Cr2O7^2- -> Mn^3+ + Cr^3+}$$ occurs in what type of condition? (a) Acidic (b) Basic (c) Neutral (d) Indeterminable
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1answer
60 views

Can concentrated sulfuric acid oxidize iron(II) to iron(III)?

Can concentrated (18 M) $\ce{H2SO4}$ oxidize $\ce{Fe^2+}$ to $\ce{Fe^3+}?$ Or does it actually block the oxidation? I read in some forum somewhere that in order to prevent $\ce{Fe^2+}$ from being ...
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1answer
268 views

Q. 36 2018 molar solubility of CaF2 at pH3 given molar solubility at pH7 and pKa of HF [closed]

This is Q36 on the 2018 Chemistry Olympiad: Calcium fluoride, $\ce{CaF2}$, has a molar solubility of $\pu{2.1e–4 mol L–1}$ at pH = 7.00. By what factor does its molar solubility increase in a ...
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2answers
415 views

Does diluting the titration flask change the molarity

I was solving the following problem on a test and I thought the answer was A, but the answer is actually D. Below is the problem and my reasoning: Answer choice B is clearly incorrect because the ...
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1answer
2k views

Is the relationship between Ka and Kb the same for all acid base pairs? [closed]

What is the relationship between $K_\mathrm{a}$ and $K_\mathrm{b}$ for acid/base reactions. I know for water $K_\mathrm{w}=K_\mathrm{a}\cdot K_\mathrm{b}$, where $K_\mathrm{w}$ is $10^{-14}$. Is this ...
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1answer
56 views

Getting from pH 2 to pH 6 by mixing with water

In our book we learned that we can get an acid to a higher $\mathrm{pH}$ by mixing it with water in the relation $\frac {1}{10} $. Now to my problem: How much water do you need in order to get the $\...
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1answer
365 views

pH value of a very dilute alkaline solution [closed]

What is the pH of a $\pu{10^-9 M}$ $\pu{NaOH}$ solution? I think it is 5.
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1answer
116 views

Pka and buffers [closed]

I'm currently studying pKa in my chemistry class, and the mathematical definition $(-log(ka))$ doesn't really explain it tangibly to me. Can you please try to simplify what pKa means and how is it ...
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1answer
119 views

Buffer solution [closed]

Prepare an aqueous buffer solution of $\mathrm{pH}=2.85$ that efficiently resists a change in pH yet contains only a small amount of buffering agent. Which one of the following weak acid together with ...
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1answer
127 views

Why can't the pH of a solution of a weak acid be calculated without the dissociation constant?

Why can't the pH of a solution of a weak acid be calculated without the dissociation constant? How can pH of weak base be determined?
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1answer
222 views

What is the acid base reaction between hydrogen telluride and sulfide ion?

$$\ce{H2Te + S^2- -> ?}$$ I tried this problem but I was confused on the fact of what the products would be because in my head I didn't think $\ce{STe}$ is a product and also it has to create ...
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2answers
3k views

Potassium hydroxide neutralization with acetic acid

I put 9% acetic acid to 60% potassium hydroxide solution to neutralize it and was hoping to see some fizzing, but didn't see any indication of them reacting. Why is that?
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1answer
51 views

Spinel or salt?

In reaction of $\ce{Al2O3}$ with $\ce{NaOH}$, we get product written as "$\ce{NaAlO2}$", "$\ce{Na2Al2O4}$" or just "$\ce{Na2O.Al2O3}$". My question is what's the real structure of this compound? ...
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1answer
9k views

Treatment of acid attack by milk [closed]

I saw a post on Facebook saying if acid falls on some body part instantly wash it by milk but after a search on google I got this link which says it will actually worsen the condition. Now I'm ...
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1answer
2k views

How do acids conduct electricity with H+ ions?

I know that ions can conduct electricity, but H+ ions has no electrons! How can it conduct electricity then. Like if we were talking about Cl- or Na+ then these ions do have electrons. But how can ...
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1answer
3k views

Hydrogen sulfide and sodium carbonate reaction

What is formed in the reaction between hydrogen sulfide and aqueous sodium carbonate? My guesses are sodium sulfite and/or sodium hydrogen sulfite. However, the equations don't seem to balance ...
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1answer
723 views

Nature of urea and it's relation with uric acid

My question is what is the nature of urea. I checked it on the Internet and according to my results, the nature of urea is basic. Then why is there uric acid? For example when we add magnesium oxide ...
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1answer
8k views

Does the reaction between sulphuric acid and ammonium hydroxide give off heat?

I have a mystery solution lab in chemistry, and I was wondering if the addition of $\ce{H2SO4}$ to $\ce{NH4OH}$ gives off heat? Or is there maybe a precipitate or color change?
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1answer
2k views

Determine if an acid base reaction will occur

I'm wondering why some acid base reactions occur, let's say for example: $$\ce{CH3CH2OH + H2O <<=> CH3CH2O- + H3O+}$$ Why does this reaction occur, because the alkoxide ion is a really ...
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1answer
4k views

How to find pKa given absorbances and pH [closed]

If the absorbance of one of the buffer solutions (pH = 4.623) was 0.319 and the absorbance of the basic solution was 0.625, what is the $\mathrm{p}K_\mathrm{a}$ of the indicator? Include activity ...
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0answers
15 views

Calculating the pH of a mixture of glycine and sodium hydroxide

What is the pH of a total 500 ml solution of 0.20 mol of glycine and 0.025 mol of NaOH? I believe the pKa of the amino group is approximately 9.6; the pKa of the carboxylic acid group is 2.8. Are ...
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0answers
34 views

Why isn't Kw = ([H+][OH-]) / [H2O], when H2O is the reactant?

For the hypothetical reaction: $$ \ce{A <=> B + C}$$ the equilibrium constant expression is written as $$\ K= \frac{[\ce B][\ce C]}{[\ce A]} $$ So, why is $ K_\mathrm w $ written as: $$ K_\...
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1answer
110 views

Lewis acid character

Which will have more lewis acid character out of $\ce{BCl3}$ and $\ce{AlCl3}$ ? My attempt: In $\ce{BCl3}$, the back bonding takes place and there is 3pπ-2pπ overlap and in $\ce{AlCl3}$ it is 3pπ-...
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1answer
160 views

Comparision of acidic strength of benzoic and peroxy benzoic acid [closed]

Out of the two which one is stronger acid ?
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1answer
461 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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1answer
146 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
112 views

Is the following procedure for antacid titration correct? [closed]

I'm trying to check which antacid is more effective by determining the amount of $\ce{HCl}$ they can neutralize. Take $\pu{10 mL}$ antacid suspension and add excess $\pu{1 M}$ $\ce{HCl}$. Back ...
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1answer
1k views

Preparing soluble salts from acids and soluble and insoluble reactants

3.15: Explain why, if soluble salts are prepared from an acid and an insoluble reactant: a) Excess of the reactant is added b) The excess reactant is removed c) The solution remaining is only salt and ...
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1answer
997 views

Why did my iodine clock reaction not work?

For the iodine clock reaction, I'm using Potassium iodide, sodium thiosulfate ($\text{0.05 M}$) and sodium peroxodisulphate ($\text{0.04 M}$) and starch as an indicator. I am varying the concentration ...
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1answer
154 views

pH of salt composed of the conjugate of strong acid and base

salt like [HA]B dissloves in water (here we don't consider its solubility) : $$\ce{HA <=>[$K_\mathrm a$] A- + H+}$$ and $$\ce{B- + H2O <=>[$K_\mathrm b$] HB + OH-}$$ usually we ...
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1answer
835 views

why the buffer capacity depends on the ratio of salt and acid in acidic buffer?

According to the Henderson–Hasselbatch equation when pH = Pka for any buffer solution then why we say that this is the best buffer?
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1answer
136 views

Polyprotic acid - How does one calculate the CONCENTRATIONS of ALL species present in a solution when you start with 0.3M NaH2PO4? [duplicate]

Can anyone give me a push in the right direction, how do I calculate the concentration of all species present in a solution with 0.3M NaH2PO4. So the concentration of H3PO4, H2PO4 -, HPO4 2-, PO4 3- ...
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3answers
110 views

Can other molecules than H+ cause a kind of acid reaction?

In our body there are plenty of other positive ions like $\ce{Na+, K+}$ and $\ce{Ca^2+}$. Can they have a similar acid reaction as $\ce{H+}$ ions can do? If not why is just $\ce{H+}$ considered as ...
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2answers
6k views

Order of acidity of water, an alcohol, an amine, and acetylene

What is the order of acidity of $\ce{H2O}$, $\ce{ROH}$, $\ce{RNH2}$, $\ce{C2H2}$? I began by forming the conjugate base of each. The conjugate bases are as follows $\ce{-OH}$, $\ce{-RO}$, $\ce{-RNH}$,...