Answer
Please see the work below.
Work Step by Step
We know that
a. $NH_3 $ is a weak base.
b. $H_3PO_4$ is a weak acid.
c. $LiOH$ is a strong base.
d. $HCOOH$ is a weak acid.
e. $H_2SO_4$ is a strong acid.
f. $HF$ is a weak acid.
g. $Ba(OH)_2$ is a strong base.