Answer: The volume of nitrogen dioxide needed to produce given amount of nitric acid is 45 L.
Step-by-step explanation:
At STP:
1 mole of a gas occupies 22.4 L of volume.
The chemical equation for the manufacturing of nitric acid is given as:

By Stoichiometry of the reaction:
of nitric acid is produced from
of nitrogen dioxide.
So, 30 L of nitric acid will be produced from =
of nitrogen dioxide.
Hence, the volume of nitrogen dioxide needed to produce given amount of nitric acid is 45 L.