Homologous Series & IUPAC Naming 🏷️

Functional Group — Compound Ka "Dil" 🏷️

Hydrocarbon chain toh bas dhaancha (skeleton) hai. Uske saath jo khaas atom ya group juda hota hai, wahi compound (yaugik) ke gun tay karta hai — use functional group kehte hain.

Functional groupFormulaPrefix / SuffixUdaharan
Halogen—Cl, —BrPrefix: chloro-, bromo-Chloroethane
Alcohol—OHSuffix: -olEthanol
Aldehyde—CHOSuffix: -alEthanal
Ketone—CO—Suffix: -onePropanone
Carboxylic acid—COOHSuffix: -oic acidEthanoic acid

👨‍👩‍👧‍👦 Homologous Series — Ek Parivaar

📌 Homologous series: Aise compounds ki shrinkhala jinme same functional group ho aur har agla sadasya pichle se —CH₂— ki ek unit zyada ho.

Har agla sadasya pichhle se sirf –CH₂– zyada METHANE CH₄ m.p. –182°C ETHANE C₂H₆ m.p. –183°C PROPANE C₃H₈ m.p. –188°C BUTANE C₄H₁₀ m.p. –138°C … +CH₂+CH₂+CH₂ Ek hi parivaar: same functional group • same general formula • gun dheere-dheere badalte hain Har step par molecular mass 14 u badhta hai
Homologous series — har agla sadasya ek –CH₂– group zyada rakhta hai.
Alcohol seriesFormulaMolecular mass farak
MethanolCH₃OH—
EthanolC₂H₅OH+14
PropanolC₃H₇OH+14
ButanolC₄H₉OH+14

📌 Homologous series ki 4 khaas baatein (board mein poocha jaata hai):
1️⃣ Sab ka general formula ek hota hai
2️⃣ Do lagataar sadasyon mein —CH₂— (yani 14 u) ka farak
3️⃣ Rasayanik gun ek jaise (same functional group)
4️⃣ Bhautik gun (M.P., B.P.) chain lambi hone ke saath dheere-dheere badalte hain

📝 IUPAC Naam Rakhne Ke 3 Steps

Step 1 — Carbon gino (sabse lambi chain mein):
1 = Meth, 2 = Eth, 3 = Prop, 4 = But, 5 = Pent, 6 = Hex

Step 2 — Bond dekho:
Sirf single = -ane | Double = -ene | Triple = -yne

Step 3 — Functional group ka suffix/prefix lagao:
—OH = -ol | —CHO = -al | —CO— = -one | —COOH = -oic acid

✔ Example 1: CH₃—CH₂—OH

2 carbon → Eth | single bond → -an | —OH → -ol
Naam = Ethanol ✓

✔ Example 2: CH₃—COOH

2 carbon (COOH ka carbon bhi ginte hain!) → Eth | single → -an | —COOH → -oic acid
Naam = Ethanoic acid ✓

✔ Example 3: CH₃—CH₂—CHO

3 carbon → Prop | single → -an | —CHO → -al
Naam = Propanal ✓

✔ Example 4: CH₂=CH₂

2 carbon → Eth | double bond → -ene
Naam = Ethene ✓

⚠️ Sabse aam galti: —CHO aur —COOH mein jo carbon hai, use bhi ginna hai! CH₃—COOH mein 2 carbon hain, 1 nahi. Isiliye wo "Methanoic" nahi "Ethanoic" acid hai.

🇮🇳 India Connection

IUPAC (International Union of Pure and Applied Chemistry) ke niyam isliye bane taaki duniya bhar ke vaigyanik ek hi bhaasha bolein. Socho — ek dawa ka naam Bharat mein kuch aur, America mein kuch aur ho toh kitni galat-fehmi hoti! Bharat ki dawa (pharma) industry duniya ki "pharmacy of the world" kehlati hai aur 200+ deshon ko dawa bhejti hai — ye tabhi sambhav hai jab har compound ka naam har jagah ek jaisa ho.

🧠 Apne Aap Ko Test Karo

Q1. CH₃—CH₂—OH ka IUPAC naam kya hai?
Q2. Homologous series ke do lagataar sadasyon mein kitna farak hota hai?
Q3. —COOH group wale compound ka suffix kya hota hai?

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