Multiple Choice
Hypobromous acid (Ka = 2.8 × 10−9) and hydrocyanic acid (Ka = 4.9 × 10−10) are both weak acids. Determine if reactants or products are favored in the following reaction.
HBrO (aq) + CN− (aq) ⇌ BrO− (aq) + HCN (aq)
3475
views
1
rank
10. Acids and Bases
Ka and Kb
Multiple Choice
Identify a Bronsted-Lowry acid with weakest conjugate base.
A
H3BO3 Ka = 5.4 × 10−10
B
HF Ka = 3.5 × 10−4
C
HNO2 Ka = 4.6 × 10−4
D
HClO Ka = 2.9 × 10−8
Verified step by step guidance1
Understand that a Bronsted-Lowry base is a substance that can accept a proton (H+). In aqueous solutions, these bases will react with water to produce hydroxide ions (OH-).
The strength of a base in water is indicated by its base dissociation constant, Kb. A larger Kb value means the base is stronger and will produce more hydroxide ions in solution.
Compare the given Kb values for each base: C2H8N2 (Kb = 8.3 x 10^-5), C5H5N (Kb = 1.7 x 10^-9), (CH3)3N (Kb = 1.0 x 10^-6), C3H7NH2 (Kb = 3.5 x 10^-4), and C6H5NH2 (Kb = 3.9 x 10^-10).
Identify the base with the largest Kb value, as this base will have the greatest concentration of hydroxide ions in solution.
Conclude that C3H7NH2, with a Kb of 3.5 x 10^-4, has the greatest concentration of hydroxide ions among the given options.
Related Videos
Related Practice
