hello everybody my name is Iman welcome back to my YouTube channel today we're going to tackle a problem set that relates to our alahh and ketones part one lecture let's go ahead and get started problem one says all of the following are true with respect to carbonal except blank a says the carbonal carbon is electrophilic B says the carbonal oxygen is electron withdrawing C says a resonance structure of the functional group places a positive charge on the carbonal carbon and Des say the pi electrons are mobile and are pulled toward the carbonal carbon now in the lecture we said that the reactivity of the carbonal can be attributed to the difference in electro negativity between the carbon and the oxygen the more electronegative oxygen atom it attracts the bonding electrons and it's therefore more electron withdrawing and thus the carbonal carbon is electrophilic all right right off the bat with those statements we know A and B are true statements we're trying to F we're trying to find which one of these options is not a true statement so A and B are true so we can go ahead and cancel those out cool now one resonance structure of the carbonal pushes electrons onto the oxygen and that does result in a positively charged carbonal carbon all right that is also a true statement what is not a true statement is that um the P electrons are mobile and are pulled toward the carbonal carbon oxygen is the more electron negative atom it is going to be electron withdrawing it is going to have a greater pull on the electrons towards it than the carbon does and so all of the following tra uh all of the following are true with respect to carbonal except answer Choice D so one is D cool two says order the following compounds by increasing boiling point we have butane butanol and buttino fantastic so now they're all they all have the parent chain but butane so they're all four carbon chains all right and so we have these three molecules and they all have four carbon chains okay one is an alkane the other is a ketone and the last well and and the third option is an alcohol which one is which well butane that's a an alkane all right this is just going to look like this 1 2 3 4 all right that's butane butanol that's an alcohol o is the giveaway so 1 2 3 4 and then there's an alcohol right there and then the last one is buttino all right so that's a ketone one buttino so this is alkan alcohol Ketone butano we're going to go ahead and draw that out one two 3 four all right right there buttino cool so we have an alkane that's butane we have an alcohol butanol and then we have a c a ketone buttino so now assuming the length of a carbon chain Remains the Same the alkane is going to consistently have the lowest boiling point the boiling point of the Ketone it's going to be elevated by the dipole in the carbon but the one that's going to have the highest B boiling point is going to be the alcohol it's further elevated by hydrogen bonding and we talked about this when we were talking about physical properties of ketones and aldhy we said that carbonal containing compounds they have higher boiling points than the equivalent alkane because of dipole interactions but alcohols are going to have even higher boiling points than carbonal because of hydrogen bonding so what that means is that butane the alkane is going to have the lowest boiling point then it's going to be followed by buttino the AL the the Ketone and then the one that is going to have the highest boiling point is going to be the alcohol butanol all right so that is going to be answer Choice B all right again I want to repeat carbonal containing compounds they're going to have higher boiling points than the equivalent alkane because of dipole interactions but alcohols are going to have even higher boiling points than carbon because of hydrogen bonding all right so the order is alkan with the lowest boiling point then buttino then butanol two is B fantastic 3 says what is the product of the reaction below all right now what we have here this is a ketone all right this is a ketone and then it is getting reacted with with this molecule right here this is a primary alcohol all right and it's just one equivalent of this alcohol all right so the reaction is between a ketone and one equivalent of alcohol and we know that all right from our lecture I'm going to even go back to the little table we saw all right all right we remember that in the presence of alcohols alahh and ketones can react to form Hemi acetal or hemiketal or acetal or ketal all right we had a little table that helped us figure out what results in what and we said that one equivalent of alcohol reacting with a ketone that's going to give us a Hemi ketle all right and a hemiketal if we come back to our notes right here all right looks like this there's two alkal groups attached at the same carbon all right and then there is an o grp group and an O group all right so if we're looking at our answer choices here all right the answer choice that aligns all right we we're getting a hemiketal all right that's the that's the a result of a ketone reacting with one equivalent of alcohol a hemiketal hemiketal all right ignore that letter right here okay and a hemiketal has two alkal groups attached to that carbon that Center carbon that carbonal carbon two alkal groups and it's going to have to be the same as the ones present in the Ketone so a methyl group ch3 and then c2h5 all right and then we're going to so the R Group is C2 H5 all right so putting all these pieces together all right we're going to have two alkal groups they have to be ch3 and C2 H5 5 all right then we're going to have an alcohol group and then an O group this o group is going to look like o C2 H5 all right we get that from the alcohol that is reacting with the Ketone the correct answer that aligns with that is going to be answer Choice C all right and we can work through these an answer choices here Choice a is a keto all right with two o groups and two R groups all right this is not a hemiketal this is a ketal we're looking for a hemiketal because our Ketone is only reacting with one equivalent one equivalent uh of alcohol all right answer Choice B all right is a Hemi acetal with an O group an O group one R Group and a hydrogen atom which is not drawn but is there all right that is also not what we're looking for and then answer Choice D all right is a ketone all right also not what we're looking for so we were looking for a hemiketal we figured it out three is going to be answer Choice C now one thing to knowe is that a hemiketal is a very unstable compound and it will react rapidly with the second equivalent of alcohol to form a ketal in Ace in acidic conditions all right but the problem's asking you all right you have a ketone and one equivalent of alcohol what are you going to theoretically get all right so that is how we solved the problem 3 is C Fantastic Four says what is the product of the reaction below okay we have a ketone here all right a ketone and then we have this primary amine all right and we know that alahh and ketones they react with ammonia and nitrogen B derivatives to form amines these are compounds with a double bond between carbon and nitrogen so keeping that in mind all right and also our flowchart that helped us visualize that right when you have a ketone or aldah and you react it with a primary amine you're going to get an amine and an amine has a double bond between a carbon and the nitrogen between the carbon and nitrogen So based off of that single fact we can begin to look at our answer choices and start to figure out which one is a reasonable possibility all right looking at the answer choices only one answer Choice stands out as having that double bond between a carbon and a nitrogen group and that is answer Choice a all right so you don't even have to do you don't really even have to do or Draw out or worry about the mechanism here all right that single Factor alone knowing that a ketone reacting with a primary amine gives you an amine will help you reach the answer that four is a all right because an amine has a double bond between a carbon and a nitrogen group fantastic five says what is the product of the reaction below we have an alahh reacting with pottassium permanganate all right alahh highes they are easily oxidized to the corresponding carboxilic acids by a strong oxidizing agent like uh pottassium permanganate all right so when you react an alahh with a strong oxidizing agent like potassium permanganate you're going to get carboxilic acid all right now you notice all right that we have one two three carbons in this aldah all right what is going to change is that you'll no longer have an alahh you will have a carboxilic acid okay so based off of that all right the answer choice that you are looking for has to involve Co group because that's what a carboxilic acid is you have two answer choices a uh B and D have those carboxilic acid groups but also don't forget that this part of your molecule doesn't disappear you're just converting an alah to a ketone so you still need that c2h5 group all right so your answer is going to be C2 H5 Co to include the carboxilic acid group that is formed by reacting an aldah with a strong oxidizing agent like potassium permanganate and so the correct answer here for five is going to be B fantastic six says what is the product of the reaction below so you have this ketone and you are reacting it with lithium aluminum hydride lithium aluminum hydride it reduces alahh to primary alcohols and it reduces ketones to secondary alcohols all right so in this reaction this Ketone is just going to be converted to a secondary alcohol all right and that it that just means that this Ketone group right here this this carbonal group now is just an alcohol group all right and that is going to correspond to answer Choice B 7 says what is the product of the reaction between benzal deide and an excess of ethanol in the presence of anhydrous hydrochloric acid cool so what we have is an alahh reacting with excess ethanol so we can think of this as like two equivalents of alcohol all right and then referencing back to our notes all right two equivalents of alcohol reacting with an alahh results in an acetal group all right and if we remember our acetal group all right we have a car our carbonal carbon attached to an alkal group the same as our aldhy to a hydrogen the same hydrogen from our alahh and two o groups all right two o our groups so let's go back to this problem all right we have benzal deide let's go ahead and draw that out all right so this is benzal deide okay and we're reacting this with excess ethanol all right so I'm going to write it a little differently than what it's given here just so that we can see what the R Group is that's going to be part of our o um group in our acetyl so again we have an acetyl that's going to be our um carbon from our carbonal it's going to be connected to the same two groups in our aldah so a hydrogen and a Benzene group and then two o groups those are going to be o C2 H5 o C2 H5 all right that is what we see in answer Choice D so seven is D all right if we look at answer choices A and B they're incorrect because they show the presence of two Benzene rings in the final product all right that's not what's going to happen and answer Choice C this shows um a Hemi acetal all right not a acetal Group which is what you would get if you're reacting an alahh with excess alcohol all right so the answer to seven is D 8 says Hemi acetals and hemiketals usually keep reacting to form a acetals and ketal why is it difficult to isolate them one says the molecules are unstable two says that the hydroxy group is rapidly protonated and lost as water under acidic conditions leaving behind reactive carbocation and three says the molecules are extremely basic and react rapidly with one another now Hemi acetals and hemiketals they are usually short-lived because the O group it will rapidly become proteinated in acidic conditions and is lost as water leaving behind a carbocation that's really susceptible to attack by an alcohol once the alcohol has been added the acetyl or ketal becomes more stable because the newly added group is less likely to become proteinated and leave as compared to an O group all right so the the statements here that are true is yes they are unstable all right and that hydroxy group is rapidly proteinated and then lost as water under acidic conditions all right statements one and two are true and they explain why it is difficult to isolate Hemi acetals and hemiketals and so eight is going to be b nine says in a hem acetal the central carbon is bonded to blank while a hem aetl is a molecule in which one equivalent of alcohol has been added to a carbonal and the carbonal oxygen has been protonated all right the groups that are are the groups that are present in a hem aetl are your hydrogen group from your aldhy your alkal group an O group and an O group all right and that's going to correspond to answer Choice a 10 says in a reaction between hydrogen cyanide butal uh alahh and Ethyl Methyl Ketone which compounds will come together to form the major product all right so this is a really good question although both the alahh and the Ketone listed will be reactive with the strongly nucleophilic hydrogen cyanide alahh are slightly more reactive towards nucleophiles than ketones for steric reasons like we've talked about in the in the lecture so what you'll do what we have happen is the alahh and the hydrogen cyanide will form the major product which will be Ayano hydron all right and so what is going to be reacting to form the major product is the butter alahh and the hydrogen cyanide that is going to be answer Choice a 11 says which of the following describes uh pyrodinium chloro uh chlorochromate PCC statement one says an oxidant that can form aldhy from primary alcohols two says an oxidant that can completely oxidize primary alcohols and three says an oxidant that can completely oxidize secondary alcohols now PCC again it's just a mild oxidant and all it can do is oxidize primary Al alcohols to aldah and secondary alcohols to ketones it is not strong enough to oxidize alcohols uh or alahh to carboxilic acids all right and so what that means is statement one is correct it is an oxidant that can form alahh from primary alcohols and it can also completely oxidize secondary alcohols to ketones so statements one and three are true 11 is C 12 CS to form form a geminal dial which of the following could attack a carbonal carbon so in a hydration reaction water adds to a carbonal forming a geminal dial all right it's a compound with two hydroxy groups on the same carbon hydrogen peroxide and potassium di chromate are oxidizing agents okay that can convert an alide to a carboxilic acid and ethanol that will react with a carbonal compound to form an acetyl or ketal if excess ethanol is available all right so the point is for this question which is asking you which of the following could attack a carbonal carbon to form a geminal dial it is strictly that this is a strictly a hydration reaction and so the answer is water water adds to a carbonal forming a geminal dial so 12 is B 13 says in a reaction between ammonia and glut alahh what is the major product so ammonia will react with an alahh like uh glut alahh to form an amine this is a condensation and a substitution reaction since uh as the the uh carbonal since the carbon double bonded to the oxygen of the carbonal will be replaced now with a carbon double bonded to a nitrogen Bond all right so the the reaction that's happening between ammonia and glut alahh is going to be um to will be to form an amine I am sorry all right so 13 is a 14 says which of the following can be used to reduce a ketone to a secondary alcohol all right so you're reducing all right reducing a ketone to a secondary alcohol we talked about hydrides like lithium aluminum hydride and sodium Borah hydde um and we said that they are reducing agents and as such they will reduce alahh and ketones to alcohols all right the other reagents that are listed here so lithium aluminum hydride is the answer answer Choice C the other reagents that are listed here these are oxidizing agents all right which will not act on a ketone all right only lithium aluminum hydride is a reducing agent from this list of options all right so 14 is C last but not least 15 says amine's naturally tozed to form blank during toiz the double bond between the carbon and the nitrogen in an amine it's moved to lie between two carbons all right and this result is an enamine all right this is a compound with a double bond and an amine okay so 15 is going to be answer Choice D and with that we end our practice problem set let me know if you have any questions comments concerns down below other than that good luck happy studying and have a beautiful beautiful day future doctors