The following reactions all have K > 1. 1. C9H7O4-(aq) + HF (aq) --> F-(aq) + HC9H7O4(aq)
2. C9H7O4-(aq) + HNO2(aq) --> HC9H7O4(aq) + NO2-(aq)
3. HF (aq) + NO2-(aq) --> HNO2(aq) + F-(aq)

Arrange the substances based on their relative base strength.

Substances:
a. NO2-
b. HC9H7O4
c. F-
d. HF
e. HNO2
f. C9H7O4-

Strength:
1. strongest base
2. intermediate base
3. weakest base
4. not a Bronsted-Lowry base