Help me with some questions :)

[Chowder]

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Alright soldiers! I am in need of assistance. Please enlighten me:

According to OAT, the answer is 7. But I counted 6. What am I doing wrong?

Kind of confused what kind of reaction is taking place. The answer is A.

The answer is D but if you asked me why ...

The answer is D. Okay so I treated this like a right triangle and luckily got the answers 7. sin(30)= x/14. But the problem did not indicate the little box symbol for a right triangle. Is there another way?

 

[nondescriptive]

for 86, i think 6 is right. The lone pair on nitrogen does not contribute to the system

 

[nondescriptive]

for 74, its the beta carbon that ethyl bromide gets added onto, therefore its A is correct. for 53, its the conjugate base of an acid so therefore its basic, slightly because it is 5%, i believe. for 34, i think they should have signaled it was a right triangle.

 

[predental89]

for 74, its the beta carbon that ethyl bromide gets added onto, therefore its A is correct. for 53, its the conjugate base of an acid so therefore its basic, slightly because it is 5%, i believe

I believe there is also a decarboxylation happening with the H+ and heat

 

[nondescriptive]

I think Chad's video explained this one real well. There is also another reaction taking place that removes the -OEt, but I can't remember. It has to do with two double bonded oxygen being next to a beta carbon and they react with each other. Can't remember but I'm sure theirs some smart people on here that can explain it better.

 

[UCSD1984]

for 74, its the beta carbon that ethyl bromide gets added onto, therefore its A is correct. for 53, its the conjugate base of an acid so therefore its basic, slightly because it is 5%, i believe. for 34, i think they should have signaled it was a right triangle.

For 74, it's the Alpha Carbon that CH2CH3 gets added to, not the Beta Carbon. This reaction is Malonic Ester Synthesis. Basically, everything to the left of the Alpha-Carbon is the leaving group (would work either way), and the alkyl portion of the alkyl halide attaches to the Alpha-Carbon.

Edit: Oh, and as far as why the EtO on the opposite side becomes OH is beyond me. I'm pretty sure Chad explained it but I simply memorized that it happens.

Second Edit: Found my notes on this. Had an acid and heat workup not occurred, the product would have been the starting compound but with OHs on each side instead of CH3CH2O, and the alkyl portion of the alkyl halide would still be attached to the Alpha-Carbon. Sorry if that explanation fails, but hopefully it helps.

Third Edit: For #86, I'm pretty sure the answer is 6. I don't see how 7 is remotely possible. Maybe someone else will chime in.

 

[nondescriptive]

For 74, it's the Alpha Carbon that CH2CH3 gets added to, not the Beta Carbon. This reaction is Malonic Ester Synthesis. Basically, everything to the left of the Alpha-Carbon is the leaving group (would work either way), and the alkyl portion of the alkyl halide attaches to the Alpha-Carbon.

Edit: Oh, and as far as why the EtO on the opposite side becomes OH is beyond me. I'm pretty sure Chad explained it but I simply memorized that it happens.

Second Edit: Found my notes on this. Had an acid and heat workup not occurred, the product would have been the starting compound but with OHs on each side instead of CH3CH2O, and the alkyl portion of the alkyl halide would still be attached to the Alpha-Carbon. Sorry if that explanation fails, but hopefully it helps.

Third Edit: For #86, I'm pretty sure the answer is 6. I don't see how 7 is remotely possible. Maybe someone else will chime in.

Correct, it was my mistake to call that the beta carbon, its the alpha carbon. My bad

 

[mestrada9447]

#74: Here is the breakdown of what is happening:
*alpha carbon is most acidic and most reactive bc it is between the 2 carbonyls
1.) NaOEt, deprotonates the alpha carbon
2.) CH3CH2Br, primary halide adds to alpha carbon via SN2 reaction
3.) H+, protonates the Oxygens making both terminal ends COOH (COO- -->COOH)
4.) heat, Thermal decarboxylation releases 1 CO2

 

[UCSD1984]

#74: Here is the breakdown of what is happening:
*alpha carbon is most acidic and most reactive bc it is between the 2 carbonyls
1.) NaOEt, deprotonates the alpha carbon
2.) CH3CH2Br, primary halide adds to alpha carbon via SN2 reaction
3.) H+, protonates the Oxygens making both terminal ends COOH (COO- -->COOH)
4.) heat, Thermal decarboxylation releases 1 CO2

Ah yea, there''s a good mechanistic explanation. That actually helped me out in understand the reaction, too...even though I already had it memorized.

 

[lol105]

The answer is D but if you asked me why ...

Out of HClO1234 series, only HClO3 and HClO4 are strongly acidic. So HClO is a weak acid. However, it has Na instead of H - thus NaClO is a strong base. The question said its concentration is 5%. Thus, strongly basic solution is diluted, resulting in a slightly basic solution.

 

[2PacClone23]

This looks like the awfully overkiller Achiever.