Haloform Reaction Full Explanation | EAPCET 2026 | Live Class with Tricks & PYQs

Added: 2026-04-29

[00:00:03]Yes. Uh good morning my dear students. Good morning all of you. Uh today we are going to discuss the live session uh which is important for EAP set examination as well as neat also. So remember so this information is whatever every day we are discussing it morning or evening or afternoon then whatever we are discussing in the chemistry topics that are useful for EAP set examination EAP set examination EAP set examination those are preparing in and kalangana then as well as then J advanc examination J advance then next one sir bit chart then also neat neat mainly so those are preparing for the neat examination all these are very important so that please subscribe my channel subscribe my channel and and share it and like So those are in the live session. So like and share my channel. So first we are going to discuss about the what is halo form reaction. Halo form reaction is what that we have to discuss. So before going to discuss the halo form reaction see my name is Lakshar. This is Ellen brand of chemistry. uh you have to subscribe my channel for more information the more examination tips more shortcut methods the more information from the chemistry so that you have to subscribe my channel and share it and uh it is useful for those are preparing for the competitive examination like J mains J advanc set need for all them it is useful then come to the point hallow form reaction so generally ally the halo form reaction is used for haloform reaction is used for the alihides are ketones some of the alcohols also alihide ketones some of the alcohols which are having alphaile group alpha methile group so mainly for alihides and ketones they're rarely for alcohols also so mainly for alihides and ketones rarely for alcohols also alihides and ketones which are having Alpha methile ketone reaction under goes in the presence of then halogen and sodium hydroxide. So hallogen in the presence of sodium hydroxide to form then methile group alpha methile group can be converted into halo form. Then the remaining carbonial group is converted into salt of caroxilic acid.

[00:03:01]So sodium salt of caroxilic acid. Say uh one of the example I will give to you.

[00:03:06]For example, in case if you take CH3 then C double bond O H.

[00:03:12]So lighting is there. So please confirm to me lighting is there. Yes. So CH3 C double bond O. So alihide. So alihide when it is treated with a H hallogen.

[00:03:25]Sir when it is treated with the NaOH NaOH see that you have how to take even this is also very important my dear students the how many moles of H hallogen how to take they will ask you question in the neat examination mainly so how many halogens are using in it then how many sodium hydroxides are using it the four moles of sodium hydroxide and three moles of chlorine atoms chlorine molecules we are using so in this reaction what happens I told that So wherever the alpha methile group is there alpha methile group this is we call alpha methile group. So alpha methile group can be converted into halo form that is chx3.

[00:04:08]So this we call halo form. Say in the place of x in the place of x what we have taken it may be chlorine or it may be bromine or it may be iodine. So what whatever if you take then chloroform, broomem, iodoform you can get then one of the point I told that is methile group can be converted into hop form.

[00:04:30]Then the remaining part of carbonile group the remaining part of carbonile group is converted into that is sodium salt of H Na sodium salt of caroxilic acid H.

[00:04:43]So Na H Na then plus still 3 moles of Na X then plus 3 moles of H2O will be formed. So this is halo form reaction.

[00:04:55]See halo form reaction sir in case how can you identify the halo form reaction you know. So in case CH3 is formed, this is actually colorless gas. Sorry, colorless liquid.

[00:05:12]Colorless liquid will be formed. Then broomem in case if you take so Br3 we call broo. This is this is also colorless.

[00:05:26]Colorless liquid.

[00:05:28]Colorless liquid with a pleasant smell.

[00:05:33]With a pleasant smell.

[00:05:36]Pleasant smell. See, look my dear students. Then oxidation takes place.

[00:05:42]Oxidation.

[00:05:44]Yellow.

[00:05:46]So yellow color.

[00:05:48]Then iodo form if you take. So CH I3. So it is it is um what we call yellow color precipitate yellow color PPT. This is yellow color PPT. So that is what in this reaction mainly we are using iodine. So the name of the reaction also we are calling iodform reaction. Even if you take chlorine chloroform we can get then broine broform we can get iodine iodopform you can get. If you take iodine easily we can identify which of the alihide or which of the ketone having so methile group alpha methile group. So iodoform test mainly we are calling it is iodoform test. If you use chlorine chloroform if you use broine broform we can get for the identification is very easy. If you take iodine that is the main reason here.

[00:06:43]Then uh come to the statement what is the haloform reaction? Alihides are ketones or ketones having having alpha methile. At least one alpha methile.

[00:07:06]At least one alpha methile.

[00:07:12]One alpha methile group under goes under goes reaction reaction with hallogens with the hallogens in the presence of NaOH.

[00:07:37]In the presence of NaOH then alpha methile group alpha methile group converted to converted to haloform.

[00:08:00]Then remaining group carbonile group carbonile group converted to caroxilic acid salt caroxilic acid salt. So this is the statement of that is halo form reaction.

[00:08:22]So look at I told that why we are calling halo form. So chlorine also we can use bromine also we can use iodine also we can use. So better use in case if you take iodine yellow precipitate clearly it can be visible so easily identify is there a positive test you can get clear of this test is generally used for differentiate between which are having alpha methiles alphaile group which do not having alphaile group clear my dear students yes look at so can I rub this see yes so Now look at so I told that even ketones also reaction takes place in this ketone is there for example for example so acetone I'm taking CH3 C double bond O CH3 so this is what we are calling acetone acetone when reaction with iodine 3 moles of iodine then plus four moles of NaOH then four moles of NaOH. So this is so one of the methile group any one of the methile group alpha methile group that will be converted into CHI3 I told right then plus then CH3 C double bond O Na CH3 C double bond O Na then sodium salt of sodium salt of caroxilic acid we call caroxilic acid Then plus N a how many moles 3 moles of Na II plus 3 moles of H2O will be formed. So this is the reaction. So this is what we call iodo form. So it is yellow color precipitate will be formed. Yellow PPT.

[00:10:15]So identification of yellow PPT which indicates that alpha methile group is present in the store. See look my students uh this is identification for identification or identification for identification for alphamile groups.

[00:10:37]alpha methile group containing containing alihides or ketos alihides or ketones. So first we are taking alihides and ketones. So for example in case then HO and CH3 CHO they will ask a question.

[00:11:06]This they will ask a question to distinguish between phmalihide and acettohide.

[00:11:13]Which test is used for the distinguish between formaldihide and acetichead? If they will ask a question. So halo form test is the best method for the identification of both because then for this CH3 CHO is there. Here alpha methile group is there. Once alpha methyl group is there it gives iodoform test. It gives iodoform test.

[00:11:42]So here due to the absence of alphamethyl group so this group do not give iodont test. Clear my dear students. Then second one. Second one sir. CH3 then C double bond O then CH3.

[00:11:59]Ketone is there. Then CH3 then CH2 then C double bond O then CH2 then CH3 like this will be there. Look my students. So both are ketones only. One is propon.

[00:12:13]One more penton. Two penton we call.

[00:12:18]So two penton that must be two penton two penton alpha position ch23 beta alpha so alpha position CH3 then it won't give test then if you come to there alpha position alpha position then CH3 is there so that it can give adop Adoptes something. So like this to distinguish between the two molecules of alihides or ketones which are having alpha methile group a hall for test is used. Clear my dear students. So what is the mechanism of halo for reaction that we'll discuss? So halo for reaction mechanism in D reactions only.

[00:13:15]So three moles of hallogen and four moles of sodium hydroxide the reaction.

[00:13:25]So first one of the general equation I'm taking look at my dear students CH3 then C double bond O H when it is treated with when it is treated with yeah tell me then three moles of allen 3 moles of X2 then four moles of NaOH right four moles of NaOH then it will be converted into look at my dear students then I told that sir methile group can be converted into CHX3 halo form plus Then then H Na sodium salt of caroxilic acid plus then 3 moles of Na X+ then 3 moles of H2O will be formed like this. See look at the mechanism now mechanism.

[00:14:09]So mechanism E reaction.

[00:14:13]So first alihide CH3 then C double bond O alihide see alihide what is happens first you know then first when it is treated with this one mole of NaOH so from the one mole of NaOH O minus will be O minus will be involved in the reaction O minus abstract alpha position of hydrogen atoms. Why? Because alpha position of hydrogen atoms are more acidic. That is the reason so in the place of alpha positions hydrogen atom it can abstract then it will be converted into H2O.

[00:14:53]So hydrogen atom this hydrogen atom it can take then it will be converted to H2. After the removal of H+ from it then CH2 bond C double bond O bond H then CH2 minus it will be formed. So of course this resonance structure also will be there that is the bond when it is shifted to there it will be sifted to there look at my dear students then CH2 double bond C then bond O minus then bond H like this will be there clear? Soion.

[00:15:37]So carbine is an intermediate in ition.

[00:15:41]So whatever then after if you take hogen any one of the hogen. So X bond X whether chlorine chlorine bond chlorine bromine bromine bond bromine iodine iodine bond iodine. See so once when it is treating with this then here what happens? Bond will be shifted to there.

[00:16:00]This bond is going to attack to the hogen immediately one of the hallogen atom will be escaped. So chlorine CH2 so bond then CH2 then bond C double bond O H listen my students carefully observe it.

[00:16:20]So one atom is replaced in the place of hydrogen atom.

[00:16:34]hydrogen of one of then in case if you use two more moles and two more moles of NaOH two more moles of NaOH and Halogen if you use then the remaining two hydrogen atoms also replaced by the H hallogen atoms clear my students yeah look at so look at how It is then C then H hallogen's halogen H hallogen then C double bond O H like this will be there clear understand all of you yes so now one more NaOH so from that base so base is going to attach to the carbonal carbon again then then what happens bond will be shifted towards that resulting what happens say look at a carbon it contains three H hallogen atoms then C the V minus will be there already H is there then CH also is there so this is this is look at the H this negative charge is going to attach negative charge is going to sift as a bond in between the carbon and oxygen then this will be sift out as C X3 minus so now this This is totally C double bond O H C double bond O H see one is H C double bond O H then this is what is that C X3 minus so bond is shifted to what on the carbon atom then C minus X3 so when once it is protonation takes place then what will be formed CH X3 will be formed CH H X3 will this is halo form. This is the mechanism of halo form reaction. My dear students see observe it carefully. The halo form reaction is halo form reaction is this. Then what happens in this reaction?

[00:18:53]So three moles of three moles of H hallogen three moles of H hallogens are replaced in the in the place of hydrogen atoms.

[00:19:05]Then after what happens? So one more m of O when it is attack on it that will be converted into caroxilic acid then this will be converted into H CH X3 that is halo for clear understand my dear students. Say I told that the reagent the chlorine or bromine or iodine in the presence of NaOH that we call haloform reagent. So what is the halo for reagent man?

[00:19:37]What is the halo for reagent? Now that is hallogens.

[00:19:42]So in the presence of NaOH hallogens in the presence of NaOH even though so not only this even though chloroform sorry bleaching powder that is Ca Cl2 also it is involved in the reaction. The same product will be for even third one. Third one look at. So that is uh sodium hypoalate. N A X nothing but N A X nothing but So that is sodium hypohalite.

[00:20:20]Sodium hypoalite even it is also involved in it. So E reagent E reagent product is same. See for example in case if I use this then one of the example I'm taking to you people. So that is C H3 then C double bond O H is S once if it is treated with the CO2 then it is what ma'am bleaching powder I told it is what bleaching powder bleaching powder so bleaching powder if you use then what will be formed in the place of methile group can converted into what I told so that will be converted into methile group only alpha methile group only can be converted into that is halo form so here chlorine is used so that's what CHL3 will be formed then plus the remaining group can be converted into that is then HO taken twice Ca so calcium salt of caroxilic acid will be formed so that is next second one if you use then CH3 3 then C double bond O H is there. C D bond O H. So in case if you use sodium hypoalate so Na or Na O actually Na Na O say for example so NaOH when it is treated with a chlorine chlorine the two moles of NaOH if you take then look at Na will be formed then Na Cl will be formed. So this is only we are calling sodium hypohalate. So sodium hypocchlorite sodium hypocchlorite. So when it is treated with this even in this case also remember my dear students then see h3 plus then this part. So that is a carbonile part H.

[00:22:27]So calcium salt of caroxile sodium salt of caroxil.

[00:22:33]So examination law then hallogen when it is treat in the pres group containing alihides ketones for reactions that you have to remember. See look at my dear student one more.

[00:22:56]So not only alihads and ketones, not only alihides and ketones. Here.

[00:23:04]Here.

[00:23:07]Even some of the alcohols. Some of alcohols.

[00:23:13]Some of the alcohols.

[00:23:18]Alcohols also also involved involved in halo for reaction.

[00:23:32]Halo form reaction. So what are those?

[00:23:35]What are those which are involved in the halo form reaction? So such as methile alpha methile containing for example CH3 then CH2 then O we call it is ethile alcohol right. So ethile alcohol also involved in it the first then the second one. So CH3 then CH then O then CH3 even this alcohol also involved that. Then third one then CH3 then CH then O then CH2 then CH3 even it is also involved at. So look at alpha methile group should be present for this alpha methile group. So alpha methyl group should be present. See for example if you take first one first one what will be there? CH3 bond CH bond OH then bond H like this will be there. See first sir sodium hypohalite Na in case if sodium hypohalite act as a oxidizing agent. Oxidizing agent oxidizing agent oxidation. So oxidation removal of hydrogen atoms from there hydrogen atoms. Then CH3 C bond H alpha methile group containing alihide.

[00:25:04]So that so that in case if you take this then again if you use Na O X or NaO CL so sodium hypocchlorite if you take then alpha methile group can be converted into CHL3 then the remaining part H NA convert also even if you use second one this is first one then second one if you take second one what will be there man so second one C H3 Secondary alcohol.

[00:25:36]Secondary alcohol.

[00:25:46]Na when it is treated with chlorine gas as a oxidizing agent. Oxidizing agent.

[00:26:02]The mild oxidizing agent. So that will be converted into here removal of hydrogen atoms from there then resulting CH3 then C double bond O CH3 will be formed. So what is formed when acetone is formed. So once acetone is formed then acetone when it is treated with then Na O again that will be converted to one of the methile group alpha methyl group can be converted into CH3 C H3 plus then the remaining part CH3 C double bond O bond O Na sodium salt of caroxilic acid is formed. So look my dear students. So not only alpha methile containing alihides and ketones and also and also when alcohols having alphaile groups alcohols having alphaile groups alcohols having alpha methile groups. So these are involved in the halo for reaction. They will ask a question based on which of the following are involved in the halo for reaction.

[00:27:19]So which of the following are involved in the halo form reaction? See look at which of the following which of the following are involved in halo for reaction.

[00:27:44]Halo for reaction.

[00:27:48]So this is the question. So options option one one is C H2 C H3 bond C H2 then CHO proponalihide is mentioned then option two they're mentioned that is so H CHO then option C they're mentioned benzaldihide option three they mentioned benjaldihide benjene attached with then CHO right then option four they are mentioned that is CH3 bond CH2 bond O see look at my students so these are the reactions alpha hydrogen alpha mythile group is there or not that we have to check it this is the alpha position so this is the alpha position and the alpha position two hydrogen atoms only is there so it won't involve in the halo for reaction reaction so alpha group so reaction alpha group Hello reaction. So this is alcohol s alolic group attached position alpha group alpha group.

[00:29:02]So oxidation oxidizing agent then3 so that it is further reaction takes place then ch x3 will be formed. Hello from so that is the reason. So these are the questions they will ask in the examination. See one of the previous year question I will explain to you people. So which are involved in the hallow form test form question.

[00:29:35]So which of the following which of the following are involved in halo for reaction yeah some of the compounds a large number of compounds we'll discuss once itself so then it will be understood clearly. So for reaction so look at my students the first compound is mentioned that is then CH3 C double bond O tell me you only is that involved in the hallow form reaction please tell me is that involve is that involved in the halo form reaction. So for reaction alpha group is there alpha. So tell me is that involve in the canaros reaction reaction. So reaction involve tell me is that involved in the aldall condensation? Yes condensation.

[00:30:53]Yes. Thank you. Thank you. Yes. Look at is that involved? Yes. Is that involved?

[00:30:58]Then second one. Second one look at. So that is they mentioned CH3 bond CH2 bond CHO. Is that involved in the haloform reaction? This is involved in the halo form reaction. Right? This is involved in the halo for reaction. Alphaile group is there. Alpha group. Alpha methyl group. So alpha methile group. So must be contain three hydrogen atoms in alpha position. So it does not involve in the halo form reaction but it will be involved in the aldall condensation because at least according to all condensation the molecule that is alihide it contains at least one alpha hydrogen.

[00:31:43]So the haloform reaction involve then one more. So third one is mentioned HC double bond H that is we know for maldihide is that involved in the halo form reaction. Haloform reaction involve is that involved in the haloform reaction. Tell me is that involved in the halo form reaction? No. So it won't involve in the haloform reaction because alpha methyl group not there. Alpha methyl group not there. Then fourth one if you take see look at the benjene attached with benjene attached with the c double bond O is there. So is that involved in the haloform reaction? So not involved in the haloform reaction because then there is no alpha alpha position methile group. So that is what it won't involve in the aloofform reaction. Then fifth one look at say fifth one the CH3 then C double bond O CH3 acetone is there is that involved in the haloform reaction my dear students yes involved in the haloform reaction because alpha methile group is there then sixth one look at sixth one then benzene attached with C double bond O CH3 now is that involved in the halo form reaction ction. Tell me my dear students is that involved in the haloform reaction? Yes, exactly involved in the halo for reaction because this is alpha position of methile group. So it will be involved in the halo form reaction. Next then seventh one look at my dear students.

[00:33:16]Then benene benzene attached with c double bond then benjene attached again. So this is we call benof phenon. Is that involved in the haloform reaction? No, it won't involve in the halo for reaction because because groups are not there. Right?

[00:33:37]Then eighth one then say look at benjene attached with benjene attached with a c double bond then ch2 bond ch3 like this is there is that involved in the halo form reaction no it won't involve in the halo form reaction because at alpha position only is there so that must be CH3 then only involve in the halo form reaction my dear student so it won't involve in the halo form reaction see look at Then ninth one. So they are given CH3.

[00:34:11]So is that involved in the halo form reaction? No, it won't involve in the halo form reaction. The alpha group functional group direct functional group functional group.

[00:34:33]So the functional group so it won't involve in the haloform reaction. So next one 10th one if you take 10th one then CH3 bond CH2 O see look at students even it is also alcohol even it is also alcohol but here and here if you observe this is alcoholic group then of course you call it as H. So H direct attach a carbon alpha.

[00:35:00]So the alpha carbon. So this is methyl group will be present. Then next one 11th one look at then benjene attached with the benjene attached with the CH2O.

[00:35:14]CH2O say is that involved? Yes involve. Is that involved? So no it won't involve in the hall form reaction because at alpha position alpha position there is no methile groups. Then 12th one look at my students. 12th one then CH3 then bond C O H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H bond CH3 see secondary alcohol is there secondary alcohol but alpha position group. So that is what it will be involved in the haloform reaction. Next one more. So look at 13th one CH3 then C double bond O then the benjene is attached at this position we call it asphenone acettophenone is that involve in the hall for reaction. Yes.

[00:36:00]Acettophen reaction involve involve. So next one that last one 14th one then that is the benjene attached with CH2 then CHO is that involved in the haloform reaction? No it won't involve in the haloform reaction. See how many are involved in the haloform in this reaction. So look at so one then second one two then third one three then is that involve no it won't involve then it won't involve then it won't involve so three after four this is then five then six so six number of six number of compounds are involved in the halo form reaction my dear students so okay understand all of you which are involved in the halo form reaction and which are not involved in the halo form reaction. Okay, understand all of you. This is about the halo form reaction. My dear students, if you have any information please note in the comment section, I will explain to you people. So whenever uh I will be free then definitely I will help to you people. So please subscribe my channel and share it and like it then this is very useful for you people those are preparing for the EAP set examination and uh and as well as advanced examination mainly for the neat examination it is useful to you people.

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