Mnemonics: Hydrocarbons | Chemistry Class 11 - NEET PDF Download

Introduction

Get ready to simplify the naming of carbon chains! These mnemonics will help you remember the prefixes for the first four carbon chains and beyond.

Prefixes for Naming Carbon Chains

Mnemonic: "Monkeys Eat Peeled Bananas"

• Monkeys: Meth (1 Carbon)
• Eat: Eth (2 Carbons)
• Peeled: Prop (3 Carbons)
• Bananas: But (4 Carbons)

Prefixes For Chains Containing Five or More Carbons

Mnemonic: "People Have Happy Oats, Not Donuts"

• People: Pent (5 Carbons)
• Have: Hex (6 Carbons)
• Happy: Hept (7 Carbons)
• Oats: Oct (8 Carbons)
• Not: Non (9 Carbons)
• Donuts: Dec (10 Carbons) 

Alkane (Single Bonds, Saturated, Substitution)

Mnemonic: "S, S, S - Simple, Saturated, Substitution"

• S - Simple: Refers to the simplicity of single bonds.
• S - Saturated: Indicates that all carbon atoms are saturated with hydrogen atoms, meaning no double or triple bonds.
• S - Substitution: Emphasizes that alkanes undergo substitution reactions where one atom or group is replaced by another.

Alkene (Addition, Multiple Bond, Unsaturated)

Mnemonic: "AMU - Addition, Multiple Bond, Unsaturated"

• A- Addition: Alkene molecules can undergo addition reactions, where atoms or groups add to the double bond.
• M- Multiple Bond: Refers to the presence of one or more double bonds between carbon atoms.
• U-Unsaturated: Alkene molecules are unsaturated with hydrogen, meaning they contain fewer hydrogen atoms than alkanes due to the double bond.

Alkyne (Addition, Triple Bond, Unsaturated)

Mnemonic: "ATU - Addition, Triple Bond, Unsaturated"

• A- Addition: Alkynes can undergo addition reactions where atoms or groups add to the triple bond.
• T- Triple Bond: Refers to the triple bond between carbon atoms, which is the characteristic feature of alkynes.
• U- Unsaturated: Alkynes are unsaturated with hydrogen due to the presence of the triple bond.

Aromatic Compounds - m-directing Groups

Mnemonic: "Queen Eats Sweet Nachos Covered with Cheese"

• Queen: Quaternary amino (-NR₃⁺)
• Eats: Ester (-COOR)
• Sweet: Sulfonic acid (-SO₃H)
• Nachos: Nitro (-NO₂)
• Covered: Carbonyl (-CHO)
• with: Carboxyl (-COOH)
• Cheese: Cyano (-CN)

Aromatic Compounds -o, -p directing Groups

Mnemonic: "A Happy Alligator Hides A Huge Pile"

• A: Alkyl (R)
• Happy: Halogen (X)
• Alligator: Alkoxyl (OR)
• Hides: Amino (-NH₂, -NHR, -NR₂)
• A: Hydroxyl (OH)
• Huge: Amide (NHCOR)
• Pile: Phenyl (C₆H₅) 

Cis–Trans Isomerism

Mnemonic: "Cis Close, Trans Apart"

• Cis: Groups are Close (on the same side).
• Trans: Groups are Apart (on opposite sides).

Mastering these mnemonics will make organic chemistry simpler and more fun, helping you quickly recall key concepts and structures with ease! Keep them handy for quick reference during studies.