Official DAT Destroyer Q&A Thread

[densaugeo]

Hi guys, since I'm currently going through the DAT Destroyer and I'm sure many of you guys are as well I felt this thread would be helpful. I usually have various questions while going through Destroyer regarding why a certain answer choice is correct or other times I am in need of a more detailed explanation.

Instead of making multiple threads each time we have questions, I thought we could just post them here and anyone can chime in with an explanation or further clarification.

Please don't post entire questions as that would be a violation of copyright. You can ask specific questions regarding a particular problem in the Destroyers.

Hopefully others find this a useful thread. Thanks!

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[sarahsal]

For dat destroyer 2016. Bio question #206 asks for a DNA sequence that is a palindrome and could be a potential restriction enzyme. The answer is choice B in the solution which is the the sequence CCTAGG, however this goes against the definition in the solutions which says that the palindrome sequence should read he same left to right? Confused.

 

[DAT Destroyer]

For dat destroyer 2016. Bio question #206 asks for a DNA sequence that is a palindrome and could be a potential restriction enzyme. The answer is choice B in the solution which is the the sequence CCTAGG, however this goes against the definition in the solutions which says that the palindrome sequence should read he same left to right? Confused.

This is a very good question. The definition of a polyndromic sequence that is implied in the solution is: A polyndromic sequence is a sequence that is read the same from 5'-3' on one strand and 5'-3' on the complimentary strand of the double helix.

Hope this helps.

 

[akimhaneul]

For question number 319 in gen Chem
It asks for the number of resonance structures for ocn-

The explanation gives the three structures I drew here with double arrows.

Why is it that it's ok to have the last one? Doesn't it have a minus 2 negative charge on nitrogen which is less electronegative than oxygen?
So shouldn't the answer be 2 not 3?

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[niel23]

Like you said, we are using a bulky base and it will be more favorable to abstract a proton from C1 compared to C2. We mainly form the Hoffman product, a double bond between C1 and C2. And therefore, our final product will be 1-bromobutane

Thank you, that makes more sense!

 

[DAT Destroyer]

For question number 319 in gen Chem
It asks for the number of resonance structures for ocn-

The explanation gives the three structures I drew here with double arrows.

Why is it that it's ok to have the last one? Doesn't it have a minus 2 negative charge on nitrogen which is less electronegative than oxygen?
So shouldn't the answer be 2 not 3?

View attachment 211392


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This is a GREAT question, that I would bet 95% of all Organic Chemistry professors are asked. What is so bad with the last resonance structure ? Yes, it has a positive charge on the O as you so perspicaciously noted, and it also has 2 formal charges on two different atoms. Well...... Can you tell me something that is good ? No ? I can. EVERY ATOM HAS THE OCTET !!! It turns out that this counts somewhat. Although certainly not the major resonance form, it IS significant. Go to any Orgo book and check out the Acylium ion. This ion also has an O with 3 bonds and a positive charge. Carbon Monoxide as well !!!! I hope this helps......remember......Give an O with 3 bonds a bit of love !

 

[akimhaneul]

DAT destroyer #35 in bio section
A hummingbird looks very similar to a sunbird. Hummingbirds live in North and South America while the sunbird is from Asia and Africa. This is an example of

Continental drift
Convergent evolution
Divergent evolution
Habitat selection
Adaptive radiation


Why is the answer B? How do we know that they are from different ancestors?

If the answer was either divergent evolution or adaptive radiation, the question should say that they look different from each other right?

 

[DAT Destroyer]

DAT destroyer #35 in bio section
A hummingbird looks very similar to a sunbird. Hummingbirds live in North and South America while the sunbird is from Asia and Africa. This is an example of

Continental drift
Convergent evolution
Divergent evolution
Habitat selection
Adaptive radiation


Why is the answer B? How do we know that they are from different ancestors?

If the answer was either divergent evolution or adaptive radiation, the question should say that they look different from each other right?

On the DAT, you must choose the best answer. Sometimes the question does not give all the background information, so you must work with what you have. Question said that two birds look similar, but they live at different locations. That is all the information you have. So the best answer would be Convergent Evolution.
You are correct, if it was a divergent evolution, they would be different, but coming from the same place, but going to the different and isolated environments.

Hope this helps.

 

[akimhaneul]

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[akimhaneul]

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[akimhaneul]

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[akimhaneul]

Question #14 in orgo destroyer

Why is it that you can use chromatography and crystallization in separating p-nitro aniline and o-nitro aniline?

Can anyone explain this one?

 

[DAT Destroyer]

Question #14 in orgo destroyer

Why is it that you can use chromatography and crystallization in separating p-nitro aniline and o-nitro aniline?

Can anyone explain this one?

The ortho, meta, and para isomer have different dipoles, thus polarities are different !!!! For example, the ortho isomer usually has a greater dipole than the para isomer. In crystallization procedures, we usually see the para isomer crystallizing first. O, m, p isomers can also be separated nicely by TLC or Column Chromatography.

Hope this helps.

Dr. Romano

 

[rbran]

Question on 2016 Destroyer, #259 - Orgo Section:

Why does the acyl halide react with the NH2 group and not with the actual benzene ring?


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[DAT Destroyer]

Question on 2016 Destroyer, #259 - Orgo Section:

Why does the acyl halide react with the NH2 group and not with the actual benzene ring?


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Great question. It looks like a Friedel Crafts reaction at first glance doesnt it ? However, this reaction has a few limitations. First off.....if an electron withdrawing group is on the ring, it fails since the ring is very deactivated. Thus rings with COOH, NO2,SO3H groups for example will not react. Another restriction is an NH2 group. Even though not an electron withdrawing group, this group can react with the AlCl3 catalyst or most other Lewis base catalysts to give a highly DEACTIVATED specie. This reaction does not even have a Lewis acid catalyst such as AlCl3. This in itself should have alerted you that this could be something different. Different indeed, as it was simply a nucleophilic acyl substitution reaction as I showed in the solution. This is an important concept that you might one day come across !!!

Hope this helps

Dr. Romano

 

[supernova11]

For Question #152 in 2014 destroyer ochem section, why does heat, H3O+ convert alcohol to an alkene? Thank you!

 

[DarthOrtho]

Hi everyone quick question from 2016 destroyer:
orgo 290) what is the reaction that adds 2 Cl to the ring? There's no catalyst like FeCl3, its just in water.
thanks

 

[Bingwen]

This maybe the wrong place to include this but I have the 2014 DAT Destroyer and Math Destroyer and plan to get the 2017 Ochem and Gen chem destroyers. Would it be worth the 2017 Math Destroyer as well or are many of the problems the same with some updates??

 

[kimball]

2016 Destroyer question #111 Gen Chem

The solution states the only temperature and not a catalyst have the ability to change the K value, however in Chad's lectures he states that temperature and the activation energy can affect the rate constant K as they are related through the Arrhenius equation :

Hope you can clear this up thanks!

 

[DarthOrtho]

2016 destroyer:
orgo 305) how do you know which alpha carbon loses the H?

 

[DAT Destroyer]

2016 destroyer:
orgo 305) how do you know which alpha carbon loses the H?

There are 2 alpha carbons. The base removes the hydrogen from the alpha carbon that is least sterically hindered to form the needed enolate anion. This will occur the fastest.

Hope this helps

Dr. Romano

 

[DAT Destroyer]

2016 Destroyer question #111 Gen Chem

The solution states the only temperature and not a catalyst have the ability to change the K value, however in Chad's lectures he states that temperature and the activation energy can affect the rate constant K as they are related through the Arrhenius equation :

Hope you can clear this up thanks!

Whoa, Whoa, Whoa, you are confusing two different constants. Changing the temperature changes both constants. Small k is a rate constant, but large K is an equilibrium constant. A catalyst changes a rate constant, but not an equilibrium constant. When dealing with equilibrium the speed of the forward reaction and the speed of the reverse reaction are increased equally and K does not change. Here's the bottom line, a catalyst generally increases small k rate constant and does not effect Keq equilibrium constant.

Hope this helps

Dr. Jim Romano

 

[DAT Destroyer]

Hi everyone quick question from 2016 destroyer:
orgo 290) what is the reaction that adds 2 Cl to the ring? There's no catalyst like FeCl3, its just in water.
thanks

A perspicacious student you are ! Normally we use a Lewis acid catalyst such as FeCl3, but it is not needed here. Once the nitro group is reduced we converted it into an NH2 group. This makes the benzene ring EXTREMELY reactive. Thus, we can get away with no catalyst,and it goes great ! I have done this reaction for over 30 years, and it goes like a bullet without the use of any catalyst. This is also the reason that we sometimes must protect the NH2 group, and slightly deactivate it to do many synthetic procedures. In this reaction, when chlorinating the ring, both ortho and para positions are both substituted.

Hope this helps.

Dr. Romano

 

[Granthj199]

I have a quick question for a question on DAT destroyer. I have the 2016 version it is problem 307 on the General chemistry section.

The problem gives a simple A + B -> C rxn and asks which does not affect the rate of the irreversible rxn. I originally thought it would be answer choice A, decreasing A because if you decrease A the equilibrium would shift to the Left but it can not do so because the reaction rate is irreversible so that would be something that would not affect the reaction rate. But of course the answer choice is D, removing C and I can't understand why. If you remove C the equilibrium would be shifted towards the right, correct? I would greatly appreciate understanding what I misunderstood in the problem.

 

[DAT Destroyer]

I have a quick question for a question on DAT destroyer. I have the 2016 version it is problem 307 on the General chemistry section.

The problem gives a simple A + B -> C rxn and asks which does not affect the rate of the irreversible rxn. I originally thought it would be answer choice A, decreasing A because if you decrease A the equilibrium would shift to the Left but it can not do so because the reaction rate is irreversible so that would be something that would not affect the reaction rate. But of course the answer choice is D, removing C and I can't understand why. If you remove C the equilibrium would be shifted towards the right, correct? I would greatly appreciate understanding what I misunderstood in the problem.

Focus on the word RATE,,,,,this is the speed at which the reaction occurs. Certainly removing a reactant would change the rate,,,,,,since less substance would be available to react. I hope this is now clear. Removing a product would NOT change the rate here since the reaction is IRREVERSIBLE. You know this since the reaction arrow points only one way !!! Again.....removal of C changes the equilibrium position,,,,,,but NOT the rate. Don't confuse the two.

I hope this helps.

Dr. Romano

 

[DarthOrtho]

2016 DAT Destroyer Gen Chem 111:

Equilibrium expression for gases are based on partial pressures, so why if the pressure is changed will K not change as well?
Thanks

 

[kimball]

2016 DAT Destroyer Gen Chem 111:

Equilibrium expression for gases are based on partial pressures, so why if the pressure is changed will K not change as well?
Thanks

If you think of it as equivalent to reaction concentration in a normal Keq expression you can see that it wouldn't affect it since the only thing that affects equilibrium expressions is Temperature


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[Bingwen]

2016 DAT Destroyer Gen Chem 111:

Equilibrium expression for gases are based on partial pressures, so why if the pressure is changed will K not change as well?
Thanks

Remember too that if you change the partial pressures of any of the gases they are no longer at equilibrium.

And if you add an inert gas K=Mol/liters. You are not changing the size of the container or the moles of the gases in the equation. Hope this helps as well.

 

[DarthOrtho]

Remember too that if you change the partial pressures of any of the gases they are no longer at equilibrium.

And if you add an inert gas K=Mol/liters. You are not changing the size of the container or the moles of the gases in the equation. Hope this helps as well.

Thanks I think I was mistaking Q for K

 

[mn94]

In order to Neutralize an Acid, one needs the concentration of H+ ions to equal to the concentration of OH- ions. In this problem, Ca(OH)2 has twice as many OH- ions as HBr. Therefore, you need to use Normality equation in order to calculate the correct concentration of acid (HBr).

Hope this helps.

But it doesn't say anywhere in the question that they want you to neutralize the H+ with OH-... should that just be implied any time there's an acid/base question?

 

[akimhaneul]

Orgo destroyer #136

Why isn't choice e considered a true double bond?

Why can't double bonds in resonance stabilized structures be considered true double bonds?

Orgo destroyer #148

Why is CH3SH a better nucleophile than others like C2H5OH? Isn't S below Oxygen in the periodic table? So aren't the electrons more stabilized due to bigger size?

 

[DAT Destroyer]

Orgo destroyer #136

Why isn't choice e considered a true double bond?

Why can't double bonds in resonance stabilized structures be considered true double bonds?

Orgo destroyer #148

Why is CH3SH a better nucleophile than others like C2H5OH? Isn't S below Oxygen in the periodic table? So aren't the electrons more stabilized due to bigger size?

Orgo destroyer #136

Why isn't choice e considered a true double bond?

Why can't double bonds in resonance stabilized structures be considered true double bonds?

The ester is not a true double bond. Resonance delocalization of the electron density can occur since it has an adjacent Oxygen. Although, not a great resonance contributor, it is significant. If you measured the double bond distance of a carbonyl group, you would find the ester to be a bit longer. This is due to the fact there is some single bond character. Resonance theory explains this nicely. Let us consider c-c bonds. A single bond is about 1.5 angstroms, a double bond is 1.3 angstroms, and a triple bond is 1.2 angstroms. In a molecule like benzene, we see about 1.4. This is between a single and a double. The actual bond is a hybrid or average .

I hope this helps

Dr. Jim Romano

 

[akimhaneul]

Orgo destroyer #136

Why isn't choice e considered a true double bond?

Why can't double bonds in resonance stabilized structures be considered true double bonds?

The ester is not a true double bond. Resonance delocalization of the electron density can occur since it has an adjacent Oxygen. Although, not a great resonance contributor, it is significant. If you measured the double bond distance of a carbonyl group, you would find the ester to be a bit longer. This is due to the fact there is some single bond character. Resonance theory explains this nicely. Let us consider c-c bonds. A single bond is about 1.5 angstroms, a double bond is 1.3 angstroms, and a triple bond is 1.2 angstroms. In a molecule like benzene, we see about 1.4. This is between a single and a double. The actual bond is a hybrid or average .

I hope this helps

Dr. Jim Romano

Thank you! Could you also please answer question 148 in orgo destroyer?


Orgo destroyer #148

Why is CH3SH a better nucleophile than others like C2H5OH? Isn't S below Oxygen in the periodic table? So aren't the electrons more stabilized due to bigger size?





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[DAT Destroyer]

Why is CH3SH a better nucleophile than others like C2H5OH? Isn't S below Oxygen in the periodic table? So aren't the electrons more stabilized due to bigger size?
Orgo destroyer #148



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[DAT Destroyer]

Why is CH3SH a better nucleophile than others like C2H5OH? Isn't S below Oxygen in the periodic table? So aren't the electrons more stabilized due to bigger size?



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Orgo destroyer #148


As a general rule of thumb.....Never bet against a Sulfur atom as a nucleophile. S is not very electronegative, and is large relative to an Oxygen nucleophile. The electrons are more loosely held. Loosely held electrons mean it can attack an electrophile more readily. If it was CH3S-, it would be even MORE nucleophilic than its neutral counterpart since a negative charge indicates the electron cloud is even more diffuse. Remember,,,,,,,these strong nucleophiles such as P, S, or CN- are super efficient for the SN2 reaction process. Hope this helps.

 

[akimhaneul]

Orgo destroyer #148


As a general rule of thumb.....Never bet against a Sulfur atom as a nucleophile. S is not very electronegative, and is large relative to an Oxygen nucleophile. The electrons are more loosely held. Loosely held electrons mean it can attack an electrophile more readily. If it was CH3S-, it would be even MORE nucleophilic than its neutral counterpart since a negative charge indicates the electron cloud is even more diffuse. Remember,,,,,,,these strong nucleophiles such as P, S, or CN- are super efficient for the SN2 reaction process. Hope this helps.

Thank you!

Orgo destroyer #149

Why can't other choices be the answer? For example, aren't 2-octanol pretty similar to 2-octanamine in terms of forming hydrogen bonding with water? So shouldn't it be hard to dissolve 2-octanol in water too?

 

[DarthOrtho]

2016 Destroyer orgo 220/gen chem 234

In the orgo question, the correct answer was that a pipet was used to transfer 15.6 ml, while a buret is used for a titration. In the gen chem question, the answer is that a buret is used. What is the difference between the two questions?
Thanks

 

[supernova11]

In Roadmap 5, 1,2-dichlorobutane reacts with 1) excess NaNH2, NH3 2) H2O to form butyne. (I was just glancing over and put butene haha) Would you be able to explain the mechanism for this reaction? Thank you!

 

[deleted816661]

In Roadmap 5, 1,2-dichlorobutane reacts with 1) excess NaNH2, NH3 2) H2O to form butene. Would you be able to explain the mechanism for this reaction? Thank you!

Shouldn't that form butyne?

 

[DAT Destroyer]

In Roadmap 5, 1,2-dichlorobutane reacts with 1) excess NaNH2, NH3 2) H2O to form butyne. (I was just glancing over and put butene haha) Would you be able to explain the mechanism for this reaction? Thank you!

This is simply the E2 mechanism., Two eliminations mechanisms occur.

Hope this helps

Dr. Romano

 

[kimball]

Hello Dr. Romano,
I am having trouble understanding the affect of polarity from functional groups when determining Rf value for thin layer chromatography.
From 2016 Destroyer:
alkanes<alkenes<ethers<esters<aldehydes/keytones<alcohols<acids

What would the effect on polarity be for compounds that are Amides or Carboxylic acids vs a Strong acid or when given a ionic compound such a sodium benzoate, does this ionic bond have a greater influence on the polarity over the benzenes non-polar character? Thank you

 

[DAT Destroyer]

Hello Dr. Romano,
I am having trouble understanding the affect of polarity from functional groups when determining Rf value for thin layer chromatography.
From 2016 Destroyer:
alkanes<alkenes<ethers<esters<aldehydes/keytones<alcohols<acids

What would the effect on polarity be for compounds that are Amides or Carboxylic acids vs a Strong acid or when given a ionic compound such a sodium benzoate, does this ionic bond have a greater influence on the polarity over the benzenes non-polar character? Thank you

The more polar spot travels slower, and the less polar spot travels faster. Rf values, on the other hand, are directly related to the rate of movement. The fastest moving spot has the highest Rf value. Therefore Rf values and polarity are inversely related. The spot with the highest Rf value is the least polar (fastest moving), and the spot with the lowest Rf value is the most polar (slowest moving). Carboxy acids are very polar, thus will move the slowest.

Yes, if an ionic group is attached to a molecule, this will increase the polarity and ****** the elution rate.

Hope this helps.

Dr. Romano

 

[IWCBTYJ]

For DAT destroyer 2016 version OG section question 40. I was sure that the answer would have been none of these for i have learned that in a basic haloform reaction, ALL alpha-hydrogens react. thus, instead of just the left 3 H being taken, i assumed that even the right hydrogens would be taken as well. I realize that the secondary carbon would not be a leaving group and hence the OH- can't attack nucleophillically, but from my college orgo class i just remember that in a BASIC condition haloform reaction, all alpha hydrogens are attacked!

 

[DAT Destroyer]

For DAT destroyer 2016 version OG section question 40. I was sure that the answer would have been none of these for i have learned that in a basic haloform reaction, ALL alpha-hydrogens react. thus, instead of just the left 3 H being taken, i assumed that even the right hydrogens would be taken as well. I realize that the secondary carbon would not be a leaving group and hence the OH- can't attack nucleophillically, but from my college orgo class i just remember that in a BASIC condition haloform reaction, all alpha hydrogens are attacked!

MECHANISM OF THE HALOFORM REACTION OF METHYL KETONES Step 1: First, an acid-base reaction. Hydroxide functions as a base and removes the acidic α-hydrogen giving the enolate. mechanism of the haloform reaction
Step 2: The nucleophilic enolate reacts with the iodine giving the halogenated ketone and an iodide ion.
Step 3: Steps 1 and 2 repeat twice more yielding the trihalogenated ketone.
Step 4: The hydroxide now reacts as a nucleophile at the electrophilic carbonyl carbon, with the C=O becoming a C-O single bond and the oxygen is now anionic.
Step 5: Reform the favourable C=O and displace a leaving group, the trihalomethyl system which is stabilised by the 3 halogens. This gives the carboxylic acid.
Step 6: An acid-base reaction. The trihalomethyl anion is protonated by the carboxylic acid, giving the carboxylate and the haloform (trihalomethane).

Consult any Organic Text if you need to see the steps. The trihalomethyl group is a decent leaving group, and attack by HO- is quite facile.

Hope this helps.

Dr. Romano

 

[DarthOrtho]

2016 Destroyer Bio 447
Is the "1 in every 50" referring to carriers or people who actually have the disease? The wording sounds like the actual disease is 1 in 50, but the answer says the parents have a 1 in 50 chance to carry the disease
Thanks

 

[DAT Destroyer]

2016 Destroyer Bio 447
Is the "1 in every 50" referring to carriers or people who actually have the disease? The wording sounds like the actual disease is 1 in 50, but the answer says the parents have a 1 in 50 chance to carry the disease
Thanks

Yes. The question says that parents who carry the trait, not have the disease. What is the possibility that 2 carriers can have a diseased child where the condition is autosomal recessive. So 1 in 50 is referring to people with the disease not carriers.

Hope this helps..

 

[IWCBTYJ]

MECHANISM OF THE HALOFORM REACTION OF METHYL KETONES Step 1: First, an acid-base reaction. Hydroxide functions as a base and removes the acidic α-hydrogen giving the enolate. mechanism of the haloform reaction
Step 2: The nucleophilic enolate reacts with the iodine giving the halogenated ketone and an iodide ion.
Step 3: Steps 1 and 2 repeat twice more yielding the trihalogenated ketone.
Step 4: The hydroxide now reacts as a nucleophile at the electrophilic carbonyl carbon, with the C=O becoming a C-O single bond and the oxygen is now anionic.
Step 5: Reform the favourable C=O and displace a leaving group, the trihalomethyl system which is stabilised by the 3 halogens. This gives the carboxylic acid.
Step 6: An acid-base reaction. The trihalomethyl anion is protonated by the carboxylic acid, giving the carboxylate and the haloform (trihalomethane).

Consult any Organic Text if you need to see the steps. The trihalomethyl group is a decent leaving group, and attack by HO- is quite facile.

Hope this helps.

Dr. Romano

Dr. Romano, thank you so much for the reply!
I guess i'm a bit still confused because like you said when Oh- is acting as the base to remove acidic hydrogens (Alpha hydrogens), there are 5 acidic hydrogens in this case instead of 3. I understand that of a normal HALOFORM reaction, only 3 hydrogens are removed but in this case because it is in a basic solution, I was expecting all 5 hydrogens to be removed.

I understand if you remove the two hydrogens on the right side of ketone group, you generate no kind of leaving group whatsoever, but should those hydrogens still be removed due to basicity of the reaction?

I think you also posted an example of what I am referring to when you look at number 73 on the 2016 orgo DAT destroyer where

I hope I have clarified my question a bit more, but thank you so much for taking the time to reply to all the questions here, looking forward to your answer!

 

[DAT Destroyer]

Dr. Romano, thank you so much for the reply!
I guess i'm a bit still confused because like you said when Oh- is acting as the base to remove acidic hydrogens (Alpha hydrogens), there are 5 acidic hydrogens in this case instead of 3. I understand that of a normal HALOFORM reaction, only 3 hydrogens are removed but in this case because it is in a basic solution, I was expecting all 5 hydrogens to be removed.

I understand if you remove the two hydrogens on the right side of ketone group, you generate no kind of leaving group whatsoever, but should those hydrogens still be removed due to basicity of the reaction?

I think you also posted an example of what I am referring to when you look at number 73 on the 2016 orgo DAT destroyer where

I hope I have clarified my question a bit more, but thank you so much for taking the time to reply to all the questions here, looking forward to your answer!

Yes, you have clarified a great question. Many times in organic chemistry, we have what is known as a competing reaction. After you have removed three hydrogens, we can INDEED have more alpha hydrogens left. However, we now have 2 choices. We can remove additional alpha hydrogens or the strong nucleophile OH- can attack the carbonyl. Alas, we are faced with a decision. Do we remove the alpha hydrogen from the other side, or should the nucleophile attack the carbonyl group which contains a reasonably good leaving group ? In actuality, BOTH can occur. Thermodynamics wins out, and the attack and departure is what occurs. We form the carboxylic acid. This is what organic chemistry is all about. Two , Three, or even SEVERAL paths are possible.....and can occur,,,,,,but one wins out because the final product is more stable. Theory is at the heart of Organic Chemistry, and when we do the experiment in lab, we TEST our theory. Your point is indeed justified. However, when this reaction is run, experiments show we get a carboxylic acid and the haloform by-product. These results strongly support the carbonyl attack and trihalomethyl departure. Let us consider the haloform reaction with 2-butanone. Let's do it your way.....we remove 3 alpha hydrogens from the methyl......no attack on the carbonyl......let's remove the 2 additional hydrogens like you say......what does this do ? Not much......There is NO LEAVING group. Methyl surely wont leave, and the trihalocarboxy group surely wont either. You are essentially at a thermodynamic DEAD END. Yes, it can occur, but nothing happens beyond this. If you were a Grad student of Chemistry, I award you the Gold Star. However, for the DAT exam.....think simple . I hope this has cleared it all up. Undergrad books....and I have read them all.....do not explore this option that you presented. It was an excellent question, and I look forward to our next question together.

Hope this helps...Dr. Jim Romano

 

[Bingwen]

I apologize if this has been asked before but I couldn't find it. The question is in regards to angiosperms. 2014 edition question 15 in Bio. Why is cross pollination, like double fertilization, not specific to angiosperms as well? I thought cross pollination could only be done by flowering plants.

 

[airstrikee]

Question 350 of the 2016 Destroyer:

I tried to solve this question using P1V1 = P2V2, giving me an answer of 41.9 torr. However, I read the explanation and it doesn't really make sense to me. I might be lacking some knowledge here, but why are we not using the equation?

Thank you for your time

 

[Queen Beach]

Good evening Dr. Romano,
This problem (#22, p154) in Odyssey does not make sense to me. I understand why you picked C from your explanation, but during the test, how can I know it's not A?
P.s I looked thru the Klein book and didnt see any problems similar to this one.... it's that methyl on "5" that's causing the confusion.