Answer
This mixture is considered a buffer.
Work Step by Step
1. Try to identify conjugate acid-base pairs**:
First solution: $HF$
Second solution: $Na^+$ and $F^-$
2. Since $HF$ is the conjugate acid of $F^-$, and they are in similar concentrations, this is a buffer.
** It has to be conjugate pair with weak electrolytes.
