Steric Inhibition of Resonance and Ortho Effect | Super-Concept & Tricks | Jee Advanced | AIIMS

Hello Guys, in this Video, we are going to explain SIR (steric inhibition of Resonance) and ortho effect. These are some of the most important and vital effects that play very important role to explain reactivity of a molecule, attacking efficiency, acidity, basicity and solvation in organic chemistry.
Basically, when two bulky groups are present nearer in a compound the repulsion takes place between the two bulky groups and due to steric crowding or vander-wall repulsion one of the group rotates about 90 degree with respect to plane to avoid cross-resonance (For better charge dispersion), this is called Steric Inhibition of Resonance or SIR effect. Many important points about SIR is discussed in details inside the lecture.
It is common observation that generally ortho substituted benzoic acids are more acidic as compared to their isomers and benzoic acids itself. Similarly, ortho substituted anilines are mostly weaker bases than aniline itself, reason is explained by ortho-effect.
Different case studies and problems based on SIR and ortho effects has been solved inside the content in detailed manner by MKA Sir.
Hope, You will enjoy the lecture.
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Thanks for watching.
Team IITian Explains.

[@IITianexplains]

If you still have doubt :- (Again explaining in detail) O-Toluic acid [3.89] > Benzoic acid [4.17]> m-Toluic acid [4.28] > p-Toluic acid [4.35] (pka values) The methyl group at ortho & para-position(4-position) destabilises Negative charge of corresponding Carboxylate ion both +I (Inductive ERG)) as well as by +H (hyperconjugation). The +H effect by methyl at meta position does not affect the carboxylate.(From here only +I effect operates) Hence m-isomer is more acidic than para-isomer. Thanks MKA Sir

[@Ajeet-Yadav-IIITD]

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[@sumukhag4755]

31:40, what about inta-molecular hydrogen bonding?

[@shridharkapse4188]

Hello sir , very good explanation , may I get your mail id or WhatsApp number pls.

[@wuzukitan5558]

The speed with which Sir tells the IUPAC name of the compound just by seeing it is still a mystery !

[@johnyjangid8541]

He is a legend

[@tanushreemanna6820]

Sir u are the best teacher of organic chemistry.......u explain every minute details of a topic and that really clears all the doubts......thank you so much sir😊

[@J2_Maths]

Yess you are right

[@_callmegupta]

Sir, you never fail to impress us with your tremendous knowledge .keep uploading !!!!!!!!!!!!

[@blahbla8599]

At 30:00 Sir in the first example , we know that more closer the +I group , more inductive effect which again destabilises the conjugate base , so by this logic para is more acidic than meta

[@muzankibutsuji5572]

sorry i won't read ur msg coz i have understood the topic very well and don't want to create any doubt

[@rom2068]

in para ..+ h is also there but in in meta + does not works

[@maheshpatil630]

But para have +m effect which overcomes +I

[@nitishmohanbatham7246]

Congratulations MKA Sir and IITian Explains Team for 35K Subscribers. Efforts of MKA Sir to make chemistry an easy to understand subject is flourishing very well .Whatever content he has provided till now is just amazing and praiseworthy with superb explanation of each concept and very good questions to check those concepts.. Just One request to him please please please please increase the frequency of chemistry and maths videos.Now we are only getting just one 30 40 minute lecture in a week. MKA Sir please do reply if you got time. Eagerly waiting for your response

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THE BEST TEACHER EVER OF ORGANIC.......

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I'm agree with you. ...

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Physics wallah

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.h

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As well as Inorganic....😎😎😎😎

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Sir u are my teacher my mentor and my inspiration .....I initially used to hate chemistry.....and I have always thought that chemistry is only about remember ing only....But u have opened a whole new world for us.......Hatts off sir...Your plus student.

[@chillpill3521]

Sir ek doubt tha Aniline +m effect show karta hai toh uska lone pair conjugation mein involved hota hai. Lekin jab hamne methyl group ortho pe dala toh resonance restrict ho gaya to ab lone pair involved nahi hai conjugation mein and is more available for reaction. To uska basic strength increase kyun nahi hua ? Thanks 🙏 a lot for the video sir all concepts were clear.

[@vaishalijamwal3294]

29:56 jitna ch3 door utna acha to para group should be more acidic... Right??

[@-_-6823]

Yes I also have the same doubt...have you confirmed this from any teacher since I am also a little confused

[@anuragchavan7900]

SIR you are the Best teacher of Chemistry, especially of organic And inorganic I have ever seen in my life!! ✌✌✌✌✌👍👍👍👍👍👍👍

[@anikitpaul9554]

guruji koi bhi class ho appki kuch naya e sikne ko milta hai ...btw apki mujhe yaad woh lecture hi kya jo samj aa jai ....thank you guruji

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Plz tell the the publisher of ur book "essentials of bonding in molecules" I am not able to get it

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Ha sir mujhe bhi cahiye

[@maghamsrinivasu3571]

Awesome Explanation. Thank You Sir.

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[@puneetsharma3241]

Last question me Ccl3 reverse hyper show karega to Para ki basicity meta se Kam honi chahiye na Kyunki meta to keval - I show karega

[@chiragkaushik7748]

Same doubt . Bahut confuse kr diya is sir ne

[@rkmourya4608]

sir u give best way of learning that difficult steric effect....thnku sir.....no one can teach like u......

[@shivkumarmaurya5058]

Sir please do lecture on. Coordination compounds

[@priyanshiijaiin5384]

Thank you very much sir may god always keep you happy

[@Vijuislive]

Sir, A huge request please upload a video containg the information of all the exceptions in p and d block elements in their properties. like NH3 has more B.P than PH3 please sir our future is in ur hand.... Lokkin forward for ur positive Reply.. THanking U..Biggest fan of MKA Sir..

[@33_Music_]

Vijuislive ! Bro this is not confusing exception that NH3 has more b.p. Than PH3 this we can think bcoz of hydrogen bonding... Actual confusing exception is why SiH3 has more b.p. Than NH3... Bcoz in this case molecular mass dominate over hydrogen bonding... 😊😊😊

[@Vijuislive]

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[@vinayk531]

Abe churiye!!!

[@yugpatel428]

sir should not be the answer for 1st question of acidic strength be 1>2>4>3 as in 3 +I effect operates nearer therefore it destabilizes more the carboxylate group than in 4

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Thank you sir...

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[@knowingcolitia5964]

Sir I have a Doubt 26:55 you explained that the SIR effect will Break the resonance in case of o-Benzoic acid but in case of aniline basicity decreases due to less solvation effect but we donot considered the EFFECT OF RESONANCE OF ANILINE as it will also not possible so basicity may increase for some extent.???????? PLZZ REPLY FAST...

[@RADHEY007]

😮5 yrs

[@33_Music_]

SIR ka effect really effective Hai... SIR has explained SIR very nicely..

[@lakshitasharma6558]

Sir 3rd question me cooh ke h ar no2 ke o ke beech me intramolecular h-bonding nhi hogi kya?

[@mightygerman]

AMAZING LECTURE SIR. THANKS SIR.

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[@apsepic5268]

Thank you sir apke is video ko dekhar main dhanya hogaya

[@realracerz3242]

31:20 Sir how is -M operating ...if COOH goes out of plane .???? Please respond it's my biggest query since a long time

[@medicalstudent8947]

Bhai ye bahut purani video hai isliye sir answer nahi karenge , comment on latest videos for any response

[@srimannarayana9056]

-M effect of -NO2 will happen with the benzene ring, the othro effect just makes the -COOH group go out of the plane and hence making +R of benzene less...(inhibits the +R effect) and lesser the +R/+M effects more acidic is the compound! :) hope it helps! stay safe!

[@realracerz3242]

@@srimannarayana9056 thanks bro for confirming.

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Please explain vander waals redius and two groups will be show overlapping.

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[@shoebmirza2216]

Sir valency of carbon in iodine and chlorine compound is incorrect.....at middle carbon..

[@deepakkeshari9367]

Thank you sir

[@shaantanukulkarni5668]

I think at 30:13 the order of first question is wrong.... please clear the doubt sir

[@antarikparashar6228]

Thanks a lot sir. Sir can you make a short video on the hybridization in MnO4- and MnO4 2-. I know that it is d3s but an explanation with the diagrams of orbitals and electrons will help a lot. Thanks

[@deekshajoshi8511]

Sir in case of o nitro aniline due to ortho effect basecity will.not increase?? Than aniline

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sir maine apki video dhekna abhi kuch din hi hua ha aap bahut acha padathe hau sir Biology and physics ke liye bhi kuch bataye please love you sir

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Your videos always help me. Thanks sir! Your are doing very good work.👍😊

[@RohitSharma-bk9wf]

Benzoic ke orthoeffect Mai acitidy increase aur aniline Mai basicity decrease ek hi to hua ??? Kya difference kya hai

[@mohitr9058]

Sir please upload faster as Mains is in January... 🙂🙂 and thank you for awesome videos...

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Sir you always choose best,interesting and tricky topic thanx sir

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Helped me a lot... Thanks sir

[@MANOJTIWARI-ni8jr]

Thank you

[@shivkumarmaurya5058]

Awesome explanation

[@33_Music_]

30:03 sir Para wala jyaada acidic hoga kyunki meta wale case me inductive effect jyaada h.. So usme negative charge on COO- barhayega Jisse meta ki acidity Kam ho jayegi..

[@IITianexplains]

O-Toluic acid [3.89] > Benzoic acid [4.17]> m-Toluic acid [4.28] > p-Toluic acid [4.35] (pka values) The methyl group at ortho & para-position(4-position) destabilises Negative charge of corresponding Carboxylate ion both +I (Inductive ERG)) as well as by +H (hyperconjugation). The +H effect by methyl at meta position does not affect the carboxylate.(From here only +I effect operates) Hence m-isomer is more acidic than para-isomer. Thanks Team IITian Explains

[@33_Music_]

Thanks sir got it... BTW it's so interesting and awesome to think hyper conjugation from Para position.. Hyper conjugation from meta position does not destabilize negative charge.. This can be felt only by drawing hyperconjugating structure in mind.. Thank u so much sir

[@fvrtnaatsbywaheedzafarqasm4325]

Best teacher ever of chemistry

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SIR MOST IMP VIDEO U CAN MAKE NOW IN INORGANIC IS DIFFERENT GASES AND THEIR PROPERTIES , HOW TO IDENTIFY THEM..

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bhai...dekhne se pehle like kro...accha to hoga hi sir ka video

[@aman-kr]

Best lecture sir.. How can anyone dislike this video.

[@sahebgarain865]

Sir agar aniline k Ortho position pe do methyl laga ho to uska to sir Kam karega, to tab aniline k resonance' inhibited ho jayaga, to tab to aniline oska lone pair donate kar payaga, because tab to NH2 gr 3 dimensionally different plane me hoga , so tab to steric Kam nehi karega ,so tab to koi acid ak us lone pair ko Le sakta ha, so tab to besicity increase hoga

[@neeteshcheeta1284]

Which is more basic between aniline and 2,4,6-tri nitro N, N dimethyl aniline

[@renukaprasadb.n9160]

Superb sir

[@gauritiwari6113]

Sir there's a doubt, No2 is an electron withdrawing group so it decreases the basicity but in case of o-nitroaniline resonance will be absent due to ortho effect so won't basicity in this case be more tha p-nitroaniline?

[@gauravjeeclasses295]

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sir kya zabardast padate ho aap .Man gaye teacher ho to hamare chemistry Guru MKA sir ke jaisa. U always inspire me to be like u.Thank u sooooooooooo much. SWASTIKA

[@IITianexplains]

Thanks Beta.

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Thanks sir

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[@chakri1105]

Super content sir

[@seepanaprakasam5969]

Sir in the basicity of amines video you told that phenyl group destabilises the (NH3)+ ion but here you told that +M of phenyl >-I of phenyl group. Please explain this sir.

[@amiyancandol4499]

Sir ye iodoform mein kyu nai hota, I mean usme to ek hi carbon pe 3 iodine hote hai to zyaada repulsion hona chahiye

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Sir also make a vdo on SIP Effect too. 🙏🙏

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Thanx sir next video kb ani h I am waiting and sir please help in physics also for aiims

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Thank you so much sir for this explanation...

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Sir please temporary effects ko bhi explain karo ak video me?

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Sir please upload Kar digiye optical isomerism(all topics) it's pending since 10 months..... 😐🙁Btw thank you for awesome video 😊

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Wait is over....

[@Subhrajeet0708]

Excellent sir . sir pls Name reaction ka kuch trick nika lo pls sir

[@satyakidas2447]

Between p-methyl benzoic acid and m-methyl benzoic acid, the p-isomer should be more acidic as it's +I effect is less due to greater distance from the -COOH group..But you have said that the p-isomer is less acidic than the m-isomer.. Why Sir please explain??

[@IITianexplains]

Because of Hyperconjugation working at para position. Hyperconjugation is more powerful phenomenon than inductive effect.

[@shubhambhardwaj6003]

wow so cool lecture sir

[@DhruvRK]

Please make a video on stereospecific stereoselective, regioselective reaction

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Yes please make video on this

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Best teacher

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[@startswithanup4318]

Thnku Sir ....