Answer to Question #167454 in General Chemistry for kali

Question

Phenol, C6H5OH, has a Ka of 1.3×10−10.

1.Write out the Ka reaction for phenol.

2. Calculate Kb for phenol’s conjugate base.

3.Is phenol a stronger or weaker acid than water? explain why.

Answer 1

a. C₆H₅OH + H₂O ---> C₆H₅O^- + H₃O⁺

b.K_b(C6H5O−)=K_w/K_a(C₆H₅OH)

Kb(C6H5O−)=K_w/K_a(C₆H₅OH)

Calculate the value of the base dissociation constant of phenoxide ion by substituting the given value of the acid dissociation constant of phenol and thatof ionic product of water as follows:

K_b(C₆H₅O−)=1.0×10^-14/1.00×10^-10

=1.00×10^-4

c. phenol is more acidic than water too, because water has more polar OH-group (in H-OH) than in phenol, because, the alkyl group releases electrons and minimizes polarity of -OH group so, the water can have more stable hydroxide ion.