11 votes

Why are sulfites often ignored in soil studies?

I think Andrew is correct in his statement: I think it's generally assumed that sulfite has a short lifetime in soil, decomposing to $\ce{SO2}$ gas or getting oxidized to sulfate. Sulfur is found in ...
9 votes
Accepted

Acidic strength of nitrophenols

I have recently answer a question about some $\mathrm{p}K_\mathrm{a}$ value discrepancies on different hydroxytetralone derivatives. As Oscar Lanzi pointed out in his answer that the major reason why ...
7 votes
Accepted

Why are sulfites often ignored in soil studies?

This article(ref.) gives you your answer: While techniques are available for determining the concentration of most S-oxides in soil, determination of soil sulphite has been largely neglected. This is ...
7 votes

Acidic strength of nitrophenols

There may be hydrogen bonding between the hydroxyl hydrogen and a nitro group oxygen in the ortho isomer, which would stabilize the proton. But 0.09 $\pu{pK_a}$ unit could be within experimental error....
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7 votes

Acidity of alcohols and basicity of amines

Qualitative attributes like strong, weak, very weak, very very weak (acid/base) have no widely accepted agreement/definition what it exactly means quantitatively. As consequence, different sources may ...
  • 33.9k
5 votes
Accepted

Acidity of alcohols and basicity of amines

There exist several sorts of weak acids. They can be weak, very weak and very very weak acids. Weak acids react with weak and strong bases. Very weak acids do not react with weak bases. They do react ...
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4 votes

Acidic strength order among hydroxytetralones

Let's look at some experimental $\mathrm{p}K_\mathrm{a}$ values of known hydroxytetralones and related compounds (Ref.1): $$ \begin{array}{l|c|c|r} \text{Entry} & \text{Compound} & \text{Ionic ...
4 votes

Number of significant figures to use in reporting the concentration of the titrand in acid-base titration

You said that you have done seven titrations, i.e., you have the set of concentrations $\{c_1, c_2, \ldots, c_7\}$. I offer you the following standard statistical approach to inform your concentration ...
4 votes
Accepted

Which hydrogen in 3-ethynyltoluene is the most acidic?

Based on the papers I've found, the answer is correct. According to Bouchoux,[1] ethynylbenzene – an analogue to the compound in question – the $\Delta G$ of deprotonation for terminal $\ce{H}$ of ...
  • 118
3 votes
Accepted

How to explain the acidity difference between these β-diketones?

The OP's question is: How can (1) be so acidic even though the two methyls cannot provide any significant stablization? Answer to that is simple. In Table II of Ref.1 shows in the entries 1-3 that $\...
3 votes

Acidity of alcohols and basicity of amines

Well, weak acids are even worse with weak bases. So try logic from 2 or 3 points rather than one. The alcohol proton is very weakly acidic, pKa 17, but much more so than hydrogen covalently bonded to ...
2 votes
Accepted

What is ionic reaction equation for reaction between carbon dioxide and limewater?

$\ce{CaCO3}$ is a precipitate. It is not made of separated $\ce{Ca^{2+}}$ and $\ce{CO3^{2-}}$ ions. So the equation is : $$\ce{Ca^{2+} + 2 OH^- + CO2 -> CaCO3 + H2O}$$ This equation may be ...
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2 votes

Calculate the pH at the equilibrium point in an acetic acid sodium hydroxide titration

At the equivalence point, there is excess neither of acetic acid neither of sodium hydroxide. The solution is equivalent to the solution of sodium acetate of the concentration $\pu{0.1 M}$, as both ...
  • 33.9k
2 votes

Acidity of alcohols and basicity of amines

Your question employs the Bronsted theory, where acids are proton donors, and bases are proton acceptors. Similar to e.g., a farmers' market with sellers and buyers, acid and base can action only in ...
  • 25.9k
2 votes

Acidity of alcohols and basicity of amines

To add to the existing answers, you can make the statement in your textbook more correct by adding "even": Alcohols are very weak acids, therefore they cannot react with even strong bases. ...
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2 votes

Why do H and Li bond so differently with a hydroxide?

If I understand your question correctly, it sounds like you are interpreting one of the hydrogens in water as being similar to the alkali metals. In other words, you expect to see a similar change as ...
1 vote

Number of significant figures to use in reporting the concentration of the titrand in acid-base titration

There are two approaches to this. Estimate the error from the estimated error of measurement (how good are you at reading a buret?). Estimate the error from the variance of multiple measurements. ...
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1 vote

pH and degree of dissociation of drugs

(Partial answer yet) If we take the H-H equation: $$\mathrm{pH} = \mathrm{p}K_\mathrm{a} + \log {\frac{[\ce{A-}]}{[\ce{HA}]}}$$ we can construct this: $$\mathrm{pH} = \mathrm{p}K_\mathrm{a,Asp} + \log ...
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1 vote

The edge case of an edge case: Vapor emissions of the descaling agent Sulfamic acid

According to the Handbook of Chemistry and Physics, sulfamic acid $\ce{NH2SO3H}$ is decomposed at about $200°$C in $\ce{NH3}$ and $\ce{SO3}$, which produces immediately ammonium bisulfate $\ce{NH4HSO4}...
  • 24.9k
1 vote
Accepted

Calculate the pH at the equilibrium point in an acetic acid sodium hydroxide titration

If the expected pH is alkaline, the hydroxide concentration will be higher than the hydronium concentration. Thus, working with K$_1$ is easier (you can neglect the hydronium concentration and focus ...
  • 35.2k
1 vote

Acidity of alcohols

As mithoron has said in the comments, alkyl basically acts as an EWG in the gas phase, as shown e.g. by Boand et al. It's easily seen that it is very very weak, which could be easily explained, as ...
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1 vote

Why is formic acid a stronger acid than acetic acid?

We may also consider solvation. Formate ion is relatively compact and thus more readily solvated by water molecules than acetate or other carboxylates, which are encumbered by their hydrocarbon groups....
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