Weak Topics - GPT FCs

What geometry does sp hybridisation give?

Linear

What geometry does sp² hybridisation give?

Trig planar

How is a σ bond formed?

End on overlap of orbitals

How is a π bond formed?

Side-on overlap of unhybridised p orbitals

Which bond prevents free rotation?

Pi bond

• What makes a good leaving group?

• Order of Halogens as leaving groups?

• It is a weak base and stable on its own

• I⁻ > Br⁻ > Cl⁻ >> F⁻

Rank carbonyl compounds by reactivity to nucleophiles

Aldehyde > Ketone > Carboxylic acid > Amide

Why are amides least reactive?

Nitrogen donates electron density by resonance, C=O less electrophilic

Which carbonyl is most electrophilic?

Aldehyde

Key feature of SN2 mechanism?

Backside attack, inversion of configuration

How many steps does SN2 have?

1

What substrates favour SN2?

Primary > secondary (tertiary = no SN2)

Front: Key feature of SN1 mechanism?

Carbocation intermediate

How many steps does SN1 have?

2

What substrates favour SN1?

Tertiary > secondary

Why are carboxylic acids stronger than alcohols?

Conjugate base is resonance-stabilised

What stabilises an acid’s conjugate base the most?

Resonance

Lower pKa means…?

Stronger acid

• Which is the strongest base: NH₃ or NH₂⁻?

• Order of basicity (strong → weak): NH₂⁻, NH₃, H₂O

• NH₂⁻

• NH₂⁻ > NH₃ > H₂O

• What can donate hydrogen bonds?

• Which molecule donates TWO hydrogen bonds?

• Can aldehydes donate hydrogen bonds?

• O–H or N–H

• Water

• No

Which is usually more stable: E or Z?

E - less steric repulsion