Chemistry - Properties of Organic chem

Properties of Organic chem

Alkane - states of matter

C1 to C4 are GASES, C5 to C15 are LIQUID, rest are SOLIDS

Alkane - Boiling point (straight & branch chain)

Boiling point of straight chain alkanes increases with increasing size of m/c

• Due to no. of e ⬆, strength of ID-ID forces ⬆

Boiling point of branching alkanes decrease while increasing branching

• Due to m/c having less SA, strength of ID-ID forces ⬇

Alkane - Reactivity

Unreactive

• are non-polar

• unreactive towards polar or ionic reagents

• not attacked by nucleophiles or electrophiles

• reacts only with non-polar reagents under UV light or heat

Alkenes - Reactivity

More reactive than alkanes

• Pi bond is weaker than sigma bond.

• Double bond is rich in e-, hence attacked by electrophiles

Halogenoalkanes - Reactivity

R -- I > R – Br > R – Cl

• Reactivity decrease due to ⬇bond length, ⬇bond energy, bond strength ⬆

• C – F bond too strong, it is unreactive

Alcohol - Volatility

• < 12 carbon atoms → Liquid at RT

• Bp of Alcohol is higher than ethers of similar Mr due to strong H-B

Alcohol - Solubility

• Solubility ⬇ as no. of carbon increases, long carbon chain less polar

• Lower alcohols are soluble due to OH group that can form H-B w water

Carbonyl Compounds

Aldehydes more reactive than ketones 

1. Size of alkyl ⬆

2. Steraic hindrance ⬆

3. Reactivity ⬇

Carboxylic acid - Boiling point

• Relatively higher due to H – O

• Higher than alcohol of similar Mr

  • Due to presence of highly electro-ve

  • Atoms in C=O & O – H bond become more polar

  • Which forms a stronger H – Bond

Carboxylic acid - Solubility

decreases as length of carbon chain increase, m/c becomes less polar

• Methanoic acid & ethanoic acid completely soluble

• Benzoic acid is soluble in hot water & crystallizes when cooled

Ester - Physical properties

• Same mlc formula as carbo acids

• Neutral

• Lower bp than carbo acids ( ❌H-bond)

• Mostly insoluble in water, but small esters are fairly soluble as chain length is short (more polar)

• Strong fruity smell

• Smallest ester will have minimum 2 carbons (draw it out, it make sense)