Acidity and Conjugate Bases in Organic Chemistry

The video tutorial explores the acidity of ethanol and acetic acid, highlighting that acetic acid is more acidic due to its lower pKa value. It explains the concept of conjugate bases, showing that ethoxide is a stronger base than acetate, making acetate more stable. The tutorial delves into the inductive effect and resonance, which contribute to the stability of acetate. It also compares cyclohexanol and phenol, demonstrating that phenol is more acidic due to its ability to stabilize its conjugate base through resonance.

Which molecule is more acidic based on pKa values?

• Both have the same acidity

• Acetic acid

• Ethanol

• Neither is acidic

What is the conjugate base of ethanol called?

• Methoxide

• Hydroxide

• Ethoxide

• Acetate

Why is the acetate ion more stable than the ethoxide ion?

• It has more hydrogen atoms

• It is less electronegative

• It has a higher pKa value

• It has a carbonyl group that withdraws electron density

What effect does the carbonyl group have on the acetate ion?

• It has no effect

• It increases the positive charge on the oxygen

• It withdraws electron density from the oxygen

• It donates electrons to the oxygen

Which molecule is more acidic, cyclohexanol or phenol?

• Neither is acidic

• Phenol

• Both are equally acidic

• Cyclohexanol

What is the conjugate base of phenol called?

• Ethoxide ion

• Phenoxide ion

• Cyclohexoxide ion

• Acetate ion

Why is the phenoxide ion more stable than the cyclohexoxide ion?

• It is less electronegative

• It has more resonance structures

• It has fewer resonance structures

• It has a higher pKa value

What is the major resonance contributor in phenoxide ion?

• The form with no negative charge

• The form with a negative charge on oxygen

• The form with a negative charge on carbon

• The form with a positive charge on oxygen

What happens to the negative charge in the resonance structures of phenoxide ion?

• It remains localized on one atom

• It is shared between multiple atoms

• It becomes a positive charge

• It disappears completely

Why is it unfavorable to place a negative charge on carbon in resonance structures?

• Carbon can stabilize negative charges better

• Carbon has more electrons than oxygen

• Carbon is more electronegative than oxygen

• Carbon is less electronegative than oxygen