Try this orgo question!

[atlanta213]

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"The reaction of 1 mole of diethyl ether with hydrobormic acid results in the production of

a. 2moles of ethly bromide.
b. 3moles of ethanol.
c. 1mole of ethlybromide and 1 mole of ethanol
d. 1 mole of methyl bromide and 1mole of propanol.

Do you think which one is answer?

I don't think the answer of kbb is right.

 

[shoombol tallah]

"The reaction of 1 mole of diethyl ether with hydrobormic acid results in the production of

a. 2moles of ethly bromide.
b. 3moles of ethanol.
c. 1mole of ethlybromide and 1 mole of ethanol
d. 1 mole of methyl bromide and 1mole of propanol.

Do you think which one is answer?

I don't think the answer of kbb is right.

does it say how many equivalents or excess of HBrreact?

 

[DRHOYA]

Hmm. So you have CH3CH2OCH2CH3 + HBr. I would think you would get CH3CH2OH + BrCH2CH3. So, based on that, would it be choice C? Or did I just mess that rxn up? What say you?

 

[harrygt]

"The reaction of 1 mole of diethyl ether with hydrobormic acid results in the production of

a. 2moles of ethly bromide.
b. 3moles of ethanol.
c. 1mole of ethlybromide and 1 mole of ethanol
d. 1 mole of methyl bromide and 1mole of propanol.

Do you think which one is answer?

I don't think the answer of kbb is right.

The answer is "C". Stong HBr is one of the few acids that can break an ether down.

 

[atlanta213]

that's what i got C!!

However, according to KBB, answer is A. I don't get this.

 

[shoombol tallah]

so while we are waiting for the answer and Im tired of looking at plant biology stuff. Ive got another question for you guys what happens when an anhydride reacts with NH3 . Ive seen one test prep say (wont mention any names because he has too many loyal fans on this site 😉 )that one mole amide and on mole of acid forms. However ive seen two other test prep services say one mole of amide forms with one mole of NH4+ -OCOCH3 ion form (thats supposed to be a carboxylic acid ion)

 

[shoombol tallah]

A can form if there is EXCESS HBr and thats why i asked earlier. I think the question is worded incorrectly.

 

[rdhdds1]

A can form if there is EXCESS HBr and thats why i asked earlier. I think the question is worded incorrectly.

I got "A". The only way that I got "A" was knowing that KBB is missing a whole lot of information on some of their questions.

Now, I am no genius so I had to do this three or four times to get "A" but the only way it works is if there is excess hydrobormic acid.

If all else fails.............look in your text book to verify.

 

[osimsDDS]

so while we are waiting for the answer and Im tired of looking at plant biology stuff. Ive got another question for you guys what happens when an anhydride reacts with NH3 . Ive seen one test prep say (wont mention any names because he has too many loyal fans on this site 😉 )that one mole amide and on mole of acid forms. However ive seen two other test prep services say one mole of amide forms with one mole of NH4+ -OCOCH3 ion form (thats supposed to be a carboxylic acid ion)

HAHAHAHA i went through that subject test today, its KAPLAN online subject test i was confused as hell about that question also...it was an anhydride with 2 moles of NH3...

 

[osimsDDS]

"The reaction of 1 mole of diethyl ether with hydrobormic acid results in the production of

a. 2moles of ethly bromide.
b. 3moles of ethanol.
c. 1mole of ethlybromide and 1 mole of ethanol
d. 1 mole of methyl bromide and 1mole of propanol.

Do you think which one is answer?

I don't think the answer of kbb is right.

Right, only if the question says excess HBr then we get A but other then that it would be C...who writes Kaplan's questions...I found a mistake in their course notebook the other day and argued with my teacher for like 10 minutes...she didnt even know what i was talking about and it was like the most simplest thing EVER...

 

[shoombol tallah]

yeah that gets on my nerves. I'm sorry but these people have no room for mistakes. They charge so much for their services they should get them right. I realize that everyone is human and we all make mistakes but they should cut into their profits just a tad and edit the crap out of their material before they publish it. So does anyone know the answer to my question ? 🙂

 

[drgreen]

But there's only ONE mol of diethyl ether. The answer can't be A unless i'm missing something.

 

[drgreen]

I was missing something, I think the CH3CH2OH then undergoes SN2, to give us answer choice A.

 

[rooney09]

Atlanta, kaplan is right the answer is A if you use one mole of H-Br...if its 2 moles, then the the alcohol fragment will be converted to an alkyl halide

 

[DRHOYA]

Atlanta, kaplan is right the answer is A if you use one mole of H-Br...if its 2 moles, then the the alcohol fragment will be converted to an alkyl halide

You mean the answer is C if one mole of H-Br is used........and A if H-Br in excess.

 

[futuredent22]

DRHOYA is right. If one mole of H-Br is used, the answer is C. However, in excess HBr, the ethyl alcohol will do another Sn2 reaction, just like drgreen showed, resulting in answer A. Kaplan should have specified that the HBr was in excess, but maybe by NOT specifying its amount we are to assume its in excess?

 

[atlanta213]

I guess there is no vague question like this on real dat. Actually, I hope so!!

Good luck everyone. We will go through this! Cheers!🙂

 

[DRHOYA]

The trick it seems with this question is the # of moles. I think that on a question, unless it says "excess" or "2 mols", then you can carry out the rxn with must 1 mol. However, in the case of grignards, then sometimes the grignard will react in 2mols.

 

[billythekid]

so while we are waiting for the answer and Im tired of looking at plant biology stuff. Ive got another question for you guys what happens when an anhydride reacts with NH3 . Ive seen one test prep say (wont mention any names because he has too many loyal fans on this site 😉 )that one mole amide and on mole of acid forms. However ive seen two other test prep services say one mole of amide forms with one mole of NH4+ -OCOCH3 ion form (thats supposed to be a carboxylic acid ion)

The answers are pretty much saying the same thing. You either have a carboxylic acid or its ion.

 

[shoombol tallah]

The answers are pretty much saying the same thing. You either have a carboxylic acid or its ion.

No the answers say you have an amide and a carboxylic acid or an amide and a carboxylic acid ion big difference.

 

[Maygyver]

But there's only ONE mol of diethyl ether. The answer can't be A unless i'm missing something.

I wouldnt think this was the mechanism with a primary carbocation.

 

[Maygyver]

A is the correct answer. It is not incorrect. Here is the mechanism:
1. Oxygen on ether grabs proton from HBr.
2. Br- attacks carbon next to oxygen and kicks electrons onto oxygen.
So far this gives ethanol and ethyl bromide.

3. Ethanol grabs proton from HBr.
4. Br- attacks carbon next to alcohol oxygen and kicks off the water molecule.

Final Answer, 2 mols ethyl bromide and water.

 

[shoombol tallah]

A is the correct answer. It is not incorrect. Here is the mechanism:
1. Oxygen on ether grabs proton from HBr.
2. Br- attacks carbon next to oxygen and kicks electrons onto oxygen.
So far this gives ethanol and ethyl bromide.

3. Ethanol grabs proton from HBr.
4. Br- attacks carbon next to alcohol oxygen and kicks off the water molecule.

Final Answer, 2 mols ethyl bromide and water.

I dont think anyone is saying that A cant be right . Its been agreed upon like 7 posts up. The only thing is in your mechanism your using two moles or two equivalents of HBr ! if there were two equivalents of HBr then yes the answer would be A, BUT the question doesn't specify if its one mole of HBr or two. If its one mole of HBr then C is perfectly correct too! Infact C is the more common way of asking the question because ethers are only cleaved by using a strong acid to form one mole of alkylhalide and one mole of alcohol.

 

[Maygyver]

I dont think anyone is saying that A cant be right . Its been agreed upon like 7 posts up. The only thing is in your mechanism your using two moles or two equivalents of HBr ! if there were two equivalents of HBr then yes the answer would be A, BUT the question doesn't specify if its one mole of HBr or two. If its one mole of HBr then C is perfectly correct too! Infact C is the more common way of asking the question because ethers are only cleaved by using a strong acid to form one mole of alkylhalide and one mole of alcohol.

Uh..it says in acid which means excess acid in most cases. If there was only 1 mol of acid it would say so.