Answer
The pH of an $Na_2S$ solution will be greater than 7.
This happens because, this salt is formed by a insignificant acid $(Na^+)$ and a strong base $(S^{2-})$, therefore, the solution is basic.
Work Step by Step
To predict the pH range of an salt:
1. Identify the ions that form this salt, and compare its strengths:
2 $Na^+$: Insignificant acid.
1 $S^{2-}$: Strong base.
Therefore: $S^{2-}$ is the stronger electrolyte, so, the solution is basic.
