Concept:
Clausius-Clapeyron equation:
\[
\ln P = -\frac{\Delta H_v}{R}\cdot \frac{1}{T} + C
\]
This is of form:
\[
y = mx + c
\]
where slope:
\[
m = -\frac{\Delta H_v}{R}
\]
Step 1: Rewrite equation in linear form.
\[
\ln P = -\frac{\Delta H_v}{R}\left(\frac{1}{T}\right) + C
\]
Step 2: Identify slope.
Comparing:
\[
\ln P \; \text{vs} \; \frac{1}{T}
\]
Slope:
\[
-\frac{\Delta H_v}{R}
\]
Final Answer:
\[
\boxed{-\frac{\Delta H_v}{R}}
\]