"The map that you need is in the hall closet." Is there a misplaced modifier in this sentence

No, there is no misplaced modifier in this sentence. The modifier "that you need" correctly describes the map.

"The teacher bought a new computer in the city with a hard drive." Is there a misplaced modifier in this sentence

Yes, there is a misplaced modifier in this sentence. The phrase "in the city" should be placed directly after the word it modifies, which is "computer." So the corrected sentence would be: "The teacher bought a new computer with a hard drive in the city."

"Mason called the police frightened by the eerie noise." Is there a misplaced modifier in this sentence

Yes, there is a misplaced modifier in this sentence. The phrase "frightened by the eerie noise" should be placed directly after the word it modifies, which is "Mason." So the corrected sentence would be: "Frightened by the eerie noise, Mason called the police."