3. The $K_a$ for four acids are:
$H_2CO_3$ = 4.5 x $10^{-7}$, $HCO_2H$ =1.8 x $10^{-4}$, $H_3C_6H_5O_7$ =7.1 x $10^{-4}$, HCN =6.2 x $10^{-10}$.
If the pH's of 0.50 mol/L solutions of these acids were measured and they were placed in order
from highest pH to lowest pH the results would be which of the following?
a. HCN, $H_3C_6H_5O_7$, $HCO_2H$, $H_2CO_3$
d. $H_3C_6H_5O_7$, $HCO_2H$, $H_2CO_3$, HCN
b. $H_2CO_3$, HCN, $H_3C_6H_5O_7$, $HCO_2H$
e. HCN, $H_2CO_3$, $H_3C_6H_5O_7$, $HCO_2H$
c. HCN, $H_2CO_3$, $HCO_2H$, $H_3C_6H_5O_7$
Explanation:
4. If the $K_a$ of a weak acid is 3.5 x $10^{-9}$, then the $K_b$ of its corresponding base must be which of the
following?
a. 2.9 x $10^{-8}$
b. 6.46
c. 2.8 x $10^{-6}$
d. 3.1 x $10^{-7}$
e. 3.4 x $10^{-7}$
Explanation
