[Duzzy]

Which of the following reactions CAN NOT be carried out in water (products are not
formed)?
A. CH3OH + KOH ® CH3OK + H2O
B. C6H5-OH (phenol) + KOH ® C6H5-OK + H2O
C. 2 CH3-COOH + Ca(OH)2 ® ( CH3COO)2Ca + 2H2O
D. maltose + H2O ® 2 glucose
E. all of these


I know the answer is A so I'm not here to try to get an answer. I don't really understand why it's A, though. Can somebody explain to me why A can't be carried out in water? Any info will be appreciated. Thanks

[Arkcon]

OK, so B actually describes itself as phenol.  That's good, because using elemental formulas only for organic compounds gets hairy rapidly.  What is the chemical in C?  It's name, and the sort of reaction it is undergoing?  Would that apply to the compound in A, which is methanol?

[Duzzy]

C would be calcium acetate and it would be a acid-base, correct? or a double displacement?

[Arkcon]

C would be calcium acetate and it would be a acid-base, correct? or a double displacement?

Great.  And phenol is also an acid, its other name is carbonic acid.  Is methanol an acid?  Does methanol and its bigger brothers ethanol and isopropanol (rubbing alcohol) attack zinc and magnesium, fizz when added to carbonates and, as in this slate of problems, neutralize an alkali like KOH?

[Duzzy]

well, alcohols are weak acids so I'm going to go with yes.

[Duzzy]

is A wrong because a base isn't produced?

[Arkcon]

well, alcohols are weak acids so I'm going to go with yes.

Umm ... no.  Aliphatic (straight carbon chain) alcohols are not Arrhenius acids.  They don't undergo the same reactions as phenol and acetic acid.  The question set seems to be tailor-made to try to make that point for you.

[Duzzy]

oooo I get it now. Thanks! The guide that I'm reviewing doesn't even mention those things at all. All it says is "Alcohols are weak acids. Weaker than water." and that's it.

[vex]

Well, that's the crux of the question. The reaction shows methanol behaving like an acid towards KOH. But, the way reactions work, KOH is always going to react with the strongest acid around. In some other solvent, that might be methanol. But in water, the strongest acid around is water, so methanol will be unaffected.

[ajkoer]

OK, apparently many Methyl salts (other examples include the Chloride, Nitrate and Sulfate) can only be successfully made in the complete absence of water. Example of one preparation route (caution: very toxic fumes):

 2 CH3OH + 2 NaCl + H2SO4 --> Na2SO4 + 2 CH3Cl

There is a high propensity for these salts to undergo hydrolysis (I would speculate the reason being that the compounds on the right of the equation below are more volatile than those on the left):

 CH3Cl + H2O --> CH3OH + 2 HCl

which is why they are toxic with even casual skin contact releasing Methyl alcohol and a strong acid (or base).

[Borek]

OK, apparently many Methyl salts (other examples include the Chloride, Nitrate and Sulfate)

Since when methyl chloride is a salt?

[ajkoer]

OK, apparently many Methyl salts (other examples include the Chloride, Nitrate and Sulfate)

Since when methyl chloride is a salt?

Here is Wikipedia's commentary:

"In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge). These component ions can be inorganic such as chloride (Cl−), as well as organic such as acetate (CH3COO−) and monatomic ions such as fluoride (F−), as well as polyatomic ions such as sulfate (SO42−).
There are several varieties of salts. Salts that hydrolyze to produce hydroxide ions when dissolved in water are basic salts and salts that hydrolyze to produce hydronium ions in water are acid salts."

So, one could call CH3Cl even an acid salt per Wiki comments. However, Methyl chloride, also called Chloromethane, R-40 or HCC 40, is more precisely part of a group of organic chemical compounds called haloalkanes.

[Borek]

OK, apparently many Methyl salts (other examples include the Chloride, Nitrate and Sulfate)

Since when methyl chloride is a salt?

Here is Wikipedia's commentary:

"In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base.

Since when methyl chloride is an ionic compound?