1. Why does the reaction shift to the right? 2. Why is phenoxide ion stable? 3. Why is phenol acidic ( compare to water )? …….
Resonance, Stability, Acid Strength 1. Resonance structures implies stability. 2. Stable anion implies the following reaction will proceed to the right, 3. Stable anion also implies that phenol is a stronger acid than water.
Which one is more acidic and why? Substituted Phenol
To examine the acid strength,
Resonance, Stability, Acid Strength 2. Fifth structure shows that nitro is an electron-withdrawing group. 1.has more resonance structures than,so it is more stable. 3. Since 1 is true, that means is more reactive than. 4. Since 3 is true, is more acidic than. 5. See page 663 for para position effect.
Resonance, Stability, Acid Strength 1. Phenol is more acidic than p-methylphenol. pK a pK a indicates that CH 3 – is an electron-donating group.
Arrange the order of acidity (from highest to lowest) of the following compounds and explain why.
Answer Key 4-nitrobenzylphenol (most acidic) phenol 4-methoxylphenol (least acidic) Reason: The nitro- on 4-nitrobenzylphenol is an electron- withdrawing group which enhances the aciditiy compare to phenol. The methoxy- of 4-methoxylphenol is an electron-donating group, thus it is less acidic than phenol.