Which of the following statements is true about phenolic disinfectants: A) They are less acidic than regular alcohols, B) They are more acidic due to resonance stabilization, C) They have a pKa similar to water, D) They are unaffected by electron-withdrawing groups?
B) They are more acidic due to resonance stabilization.
What is the role of phenol red in the urea medium?
Phenol red acts as a pH indicator in the urea medium, changing color to indicate the presence of urease activity.
Why are phenols more acidic than regular alcohols?
Phenols are more acidic due to the resonance stabilization of their conjugate base, phenoxide, which allows the negative charge to be delocalized within the ring.
How do electron-withdrawing groups affect the acidity of phenols?
Electron-withdrawing groups stabilize the conjugate base by decreasing electron density in the ring, thus increasing the acidity of phenols.
What is the effect of electron-donating groups on phenol acidity?
Electron-donating groups increase electron density, destabilizing the conjugate base and making the phenol less acidic.
How does the position of substituents on the phenol ring influence acidity?
Substituents at the ortho and para positions have a greater impact on acidity due to resonance pathways, while meta position substituents have a lesser effect.
What is the pKa of phenol compared to typical alcohols?
The pKa of phenol is around 10, which is significantly lower than that of typical alcohols, which is about 16.
Why do ortho and para positions have a greater impact on phenol acidity than the meta position?
The negative charge in the phenoxide ion resonates to the ortho and para positions, but not to the meta position, affecting acidity more at ortho and para.
What does the acronym 'WAP' stand for in the context of phenol acidity?
'WAP' stands for Withdrawing group at the Ortho and Para positions, indicating increased acidity.
What happens to the acidity of phenol when electron-donating groups are in the meta position?
The acidity is only slightly less affected because the negative charge in the phenoxide ion does not resonate to the meta position.