The understandable notes- Carbon and its compounds, Class 10 Part-4

 Naming of Alkenes & Alkynes

The compound containg double bond are called alkenes and the compounds containing triple bonds are called alkynes.

( Jinhone pichla ek bhi part nhi padha unke liye bata deta hu ki jin compounds mai double bond hote hai unhe alkenes bolte hai aur jinme triple bond hote hai unhe alkynes bolte hai. )

For alkenes we use the primary suffix "ene" and for alkynes we use primary suffix "yne". Ethene is the simplest alkene.

( Ab dekho jaise alkanes mai single bond hone ke karan ane to use krte the vaise hi alkenes mai ene ko or alkynes mai yne to use krte hai ek baat aur yaad rakhna ki double bond or triple bond ki priority same hoti hai. Chalo ise likh hi deta hu.)

The priority of double bond and triple bond is same unless both are present in same position from opposite side. If double bond is positioned at third from one side and triple bond is also positioned at other side at same position then we check that the whole compound should get lowest locant. But if there is no more multiple bond then we give priority to double bond as it comes alphabetically first.

( Double bond aur triple bond ki priority same hoti hai jab tak unki positions mai difference ho. Agar ek taraf se numbering krne par hume 3 position par double bond mil raha hai aur dusri taraf se numbering krne par hume triple bond mil raha hai vo bhi same position pr to hum double bond ko priority denge kyonki vo alphabetically first aata hai.  Lekin agar is condition ke baad compound mai aur bhi double aur triple bond hai to hum pehle ye dekhenge ki sabse jyada lowest number kis tarah assign kre. Jaise substituents ke time pr kiya tha bas wahi hai.)

1) Select the longest chain that contains the maximum number of double bond and triple bond. If containing double bond and triple bond makes the chain shorter than make it shorter because priority of multiple bonds is more than substituents  and branching.

( Ab rule mai ek chotu sa change hai. Aapko vo chain select krni hai jisme double bond aur triple bond maximum hai. Haan to ye us compound ki baat ho rahi hai jisme functional group present na ho to confuse mat hona. Agar sare double bonds aur triple bonds ko ek chain mai lane ke liye chain ko chota krna pad raha hai to kar do. Agar branches ki bhi branches ban rahi hai to bana do. Vaise itne jyada conceptual question nhi aaenge jisme internal branching krni pade pr vaise bata raha hu ki multiple bond ke aage substituent ki koi aukat nhi hai. Chalo naming ko in compounds se sikhte hai.)

Name the compound

Select the longest chain. As you can see there are only two carbons so longest chain will be of two only. Also there is no branches but only a double bond. So we use the primary suffix 

The name of the compound will be- ethane 

Ethene

( Dekho is compound mai to kya batana is compound mai sirf do atom hai to eth or ek single bond hai to ene. Chalo jab tum compounds ke complete structure banaoge to tumhe ek baat ka pata hona chahiye ki number or hydrigen kitne hote hai. Chalo abhi alkenes kai liye bata deta hu ki number of hrdrogen double hote hai carbon atoms ke comparison mai. )

Number of hydrogen in ALKANES, ALKENES,  ALKYNES 

In alkanes, the number of hydrogen is (2n+2) where n is the number of carbon atoms. In alkenes the number of hydrogen atom is '2n' where n is the number of carbon atoms. And in alkynes the number of hydrogen atoms is '2n-2'. Also remember that this formula works only wothout functional group or halogen substituents. With branches of methyl, ethyl it can work.

( Dekho ek chota sa topic hai. Topic bhi kya ek line hi hai ki alkanes mai hyfrogen ke kitne number hote hai, alkenes mai kitne hote hai aur alkynes mai kitne hote hai. Ye bas check krne ke liye hota hai ki compound mai sahi number oh hydrogen hao ya galat kyonki kai baar students 5 bond bana dete hai carbon ke.)

Name the compound

( Chalo ab sare rules jo maine is part mai bataye hai aur jo pichle part me bataye hai unka use krke is compound ka naamkaran karo. Chalo ek hint de deta hu ki ye jo c3h8 hai ye propane hai kyunki iski number of hrdrogen carbon ke atoms double aur plus 2 hai. Ab dekho mai baar baar to ye batane ki nhi ki tum yeh wali chain select kroge aur ye is liye galat hai to mai sidha sidha sahi answer hi batunga. Agar kisi ko aur doublt ho to pichla part dhyan se padh lena aur practice bhi kar lena. Haan to chalo iska solution krte hai.)

Solution 

Select the longest possible continuous chain which contains maximum double and triple bonds. So the chain will be 

If you are thinking that including the C3H8 group will result in a larger chain then you are correct but then we are unable to include all double bond and triple bond. So we let it as and make the cgain including all double and triple bonds.

( Haan to longest chain ye banegi jo maine dikhai hai. Agar propane wale group ko longest chain mai include kiya to vo sare double aur triple bonds ko contain nhi kr paaegi aur kyonki double bond aur triple bond ki priority substituents se jyada hoti hai isi liye longest chain ye wali banegi.)

Then number the compound we give number so that double bond or triple bond get lowest locant. But in the above compound both get same position. So we look at substituent, if we number from double bond side then we got substituent at postion 3 while from numbering triple bond side we get substituent at position 4. So we prefer numbering from double bond side.

 (  Ab dekho numbering ke time pr hume ye dhtan rakhna hota hai ki double bond ya triple bond to lowest locant mile. Ab dono taraf se hi numbering krne pr 2 position par multiple bond mil rha hai. To yaha par baat tie ho gayi. Ab hum dekhenge ki compound  mai aur kya kya present hai. To is compound mai ek substituent bhi hai. Aur agar hum double bond wali side se numbering kre tabhi us compound ko lowest locant milega. To bas ye confirm ho gaya. Ab dekho agar substituent present na hota to hum alphabetically preference ke karan double bond ko priority de dete par kyonki yaha substituent present hai to iski jarurat nahi padi.)

The name of the compound will be

3-propyl hex 2-en 4-yne.

Now if you are condused that why i have written en and not ene so in nomenclature when a,e,i,o,u,y comes in sequence then we delete the previous letter.

( Agar ye doubt ho raha hai ki ene ki jagah pr sirf en kyo likha hai to nomenclature mai jaha jaha a,e,i,o,u,y ek sath aate hai waha hum pehle wale alphabet ko delete kr dete hai. Av agar yne ki jagah diyne hota to fir ene ko complete likhte. To chalo alkenes aur alkynes ki bhi naming ho gayi ab chalte hai functional group ki taraf. )

Number of compounds containing functional group 

Functional group is a atom or group of atoms that determines the chemical property and nature of reaction of compound. Functional group has the most priority in nomenclature.

( functional group ek atom ya for group of atom yani ki ek molecule hota hai jinse kisi bhi compound ki chemical property depend krti hai. Dekho functional group ki priority sabse jyada hoti aur khushi ki baat ye hai ki 15 se bhi jyada functional groups mai se tumhare paas sirf 3-4 hai. To jo jo hai vo one by one tumhe batata hu.)

Aldehyde,  Ketone,  Alcohol 

(To ye main functional groups hai jo tumhe padhne hai. Halogen Cl,Br,I,F to substituent hote hai baki bache ye teen. Ab common rules to pata hi hai isi liye aage ka nomenclature kafi easy ho jayega.)

Select the longest chain that contains the functional group.If choosing functional group makes the doubke bond out of chain then do it.

( To ek naya or last rule nomenclature ka ki vo chain select karo jisme functional group ho. Ek baat yaad rakhna ki halogens substituent hote hai na ki functional group. To main chain mai functional group hona hi chahiye. Aur jitne double ya triple bond ho sakte hai vo bhi aa jane chahiye. Aur tumhari class mai aa bhi jayenge tension mat lo. Na to tumhe double bond ya triple bond to branches ki tarah padhne ki jarurat hai na hi functional group ko. To bas teen hi functional group hai aur teeno easy hai. Inke baad circular compound padhenge.)

Alcohol

Molecule-  -OH

Structure-  -O-H

Suffix- ol

Naming - add ol as secondary suffix.

Now name the following compound.

Number of atoms- 1

Word root- Meth

PRIMARY SUFFIX- ANE

SECONDARY SUFFIX- ol

Name of compound- Methane+ ol= Methanol

Because we delete e from methane as e and o comes continuosly.

( Isme to kuch samjhane ki jarurat nhi hai ye to samajh aa hi gaya hoga. Sare rules purane wale hi to hai.)

Name the compound

Select the longest chain that contains all functional groups. Functional group has most priority.

(  To dekho sabse longest chain select krni hai jisme ki sare functional group ke atom ho. To mere hisab se to yehi honi chahiye lekin agar aapke dimag mai koi aur bhi chain ban rahi hai to nikal do vo galat hai. Kyunki mujhe 5 saal ka experience hai. Mere hisab se numbering mai bhi kuch batana jaroori nhi hai. Right to left hi hogi. Agar left side ke pehle carbon par double bond bhi aa jata to bhi numbering yehi hoti kyunki functional group ki priority jyada hoti hai as compared to double or triple bond. )

Substituent- Propyl on position 2

Name of compound

2-propyl butane 1,3- diol.

( Chalo iski naming samjha deta hu. Sabse pehle to humne substituent likh diya psotion ke sath. Ab iske baad humne ye dekho ki do functional group present hai. Do isme di word ka use hoga. Ab agar di word ka use hoga to butane ke last e ko delete nhi kiya jayega or use aise hi rakha jayega. Agar ek hi functional group present hota to iska naam butanol hota. Chalo alcohols to khatam ab aldehyde or ketone ko sath mai padhte hai kyunki vo dono bhai bhai hai.)

Naming of Aldehydes and Ketones

Aldehydes are the molecule which contains a double bonded oxygen and a single bonded hydrogen. It is a terminal functional group. It means it is present only on the end positions of the molecule. Ketones also contain are double bonded oxygen with carbon but they lack hydrogen atom. This is the only difference between ketone and Aldehyde that ketone are not terminal functional group ehile aldehydes are. Also the carbon atom which is double bonded to oxygen must be bonded to alkyl group on both side. 

Aldehyde structure  

As you can see that this structure is only possible when the carbon is at terminal position.

( Is structure ko dhyan se padho aur samjho ki ye sirf tabhi possible hai jab carbon terminal position par ho. Agar carbon terminal postion par nahi hoga to uski do valency satisfy hogi aur agar do valency satisfy hogi to double bonded oxygen aur single bonded hydrogen kaise aa sakega. Ye to common sense wali baat hai. Ab methanal or ethanal ka structure draw karo practice ke liye.)

Secondary suffix- al

Ketones structure

Secondary suffix- one

Where R and R' may be same or different alkyl group.

( Ab dekho ketone ka structure is structure mai aap dekh sakte hai ki carbon ke dono taraf alkyl group present hai. Ab ek carbon se to ketone bonded hai aur do alkyl group ki bhi required hai to iska matlab ye hai ki simplest ketone propane se hi banega. Iska naam shayad propanone hoga. Chalo iska structure bana kar check karo book se ya internet se. )

Name the following compound

Select the longest possible chain that contains functional group and double bond.

( To dekho sabse pehle to vo chain select karoge jisme functional group or maximum double ya triple bond ho. Mere hisab se to accurate longest chain ye banegi jo niche dikhai hai baki tumhare dimag mai abhi bhi koi aur chal rahi hai to tumhe kafi hard practice ki jarorat hai, nomenclature me.)

Now number the compound.

( Yaar dekho is compound ki numbering krne se pehle sare rules ka pata hona chahiye. To numbering hum sabse pehle functional group ki krte hai lekin is compound mai to dono end par aldehyde group hai. Haan ye aise bhi likha aa sakta hai confuse mat hona. Yaad rakhna ki agar terminal carbon par double bonded oxygen hai to vo aldehyde group hi hai. Chalo ye to tie ho gaya ab iske baad aata hai double bond. To dono taraf se numbering krne par double bond second position par aa raha hai to ye bhi tie ho gaya. Ab teesri chix hai substituent aur is compound mai first substituent 2 position par aur second substituent 3 position par milegi. To ye bhi tie ho gaya. Ab yaad karo ki kai 100 saal pehle maine bataya tha ki substituent ki position bhi agar tie ho jati hai to fir hume alphabetically decide krna padta hai.To methyl aur butyl mai se mere hisab se butyl ko priority milegi. Dekho ki is compound mai functional group bhi hai, double bond bhi hai fir bhi numbering substituent par depend krti hai. Agar butyl ki jagah methyl hota to fir kaise bhi numbering kar lo answer same aayega. Iski numbering hi sabse bada issue tha baki to samajh aa hi jayega)

Name of the compound is- 

2-butyl 3-methyl butane 1,4-dial.

Name the following compound.

( Dekho mai to same same rule l8kh kar thak gaya hu. Bas is compound ka naam likh raha hu)

1-bromo 3-chloro 4-fluoro butan-2-one.

( Dekho isme kuch jyada to samjhane ka nahi hai agar puchle sare rules yaad hai ko ye kuch nahi hai. Dekho 10th class ke hisab se ye kafi advance hai. Yani ki agar in sare rules ko yaad kr lo to nomenclature mai koi dikkat nahi aaegi. Vaise to ye sirf ek topic hai lekin vo bache jinhe aage science padhni hai unki liye ye bahut important hai. To bas is part mai ye  nomenclature khatam krte hai agle part mai kuch specific compounds hai aur unka structure jo yaad krna padega. Ek baat humesha yaad rakhna ki organic chemistry ek yaad krne wala subject hai. Dekho chapter lengthy hai to teen char part aur lega par iski gurantee deta hu ki kuch doubt nahi rahega. Dekho ek functional group aur hai lekin vo tumhare syllabus mai se cut hai. Kafi important hai isi liye padha deta hu par agar kisi ko nahi padhna to koi baat nahi. )

CARBOXYLIC ACID

STRUCTURE- COOH

Secondary suffix- oic acid

For example- methanoic acid,ethanoic acid etc.

Name the compound

Name of the compound will be butanoic acid.

( Ye to bilkul simple sa hi hai. 4 carbon hai aur last mai carboxylic acid hai bas.)

Name the compound.

We have substituent at different positions but numbering is done from functional group. Also remember that substituents are written alphabetically irrespective of position. So the name of the compound will.

2-chloro 3-fluoro 2-iodo 3-methyl butanoic acid.