Question

The relative strength of a conjugate acid or base can be judged by:

• A. $k_a$ of the subtance
• B. $k_b$ value of the subtance
• C. both A or B
• D. none of above

Answer 1

The correct option is C both A or B

All acids have a conjugate base that forms when they react with water, and similarly, all bases have a conjugate acid that reacts when they form with water. We can judge the relative strength of a conjugate by the $K_a$ or $K_b$ value of the subtance because $K_a\times K_b$ is equal to the ionization constant of water, $K_w$ which is equal to $1\times {10}^{-14}$. The higher the $K_a$, the stronger the acid is, and the weaker its conjugate base is. Similarly, the higher the$K_b$, the stronger the substance is as a base, and the more weakly acidic its conjugate acid is.