You will be given a definition of a task first, then some input of the task.
Given a scientific passage and an answer, generate a question for the given answer.

Passage: Some solutions have special properties because they are acids. Orange juice is an example. It contains an acid called citric acid. It makes orange juice taste sour. Some solutions are bases rather than acids. Answer: citric acid
Output:
What in orange juice makes it taste sour?