How many times does the citric acid cycle occur for each molecule of glucose?

For one glucose molecule, the citric acid cycle can occur twice (2).

Glucose which has six carbons is broken down in glycolysis to produce two molecules of the three carbon Pyruvate. Now that you have the Pyruvate, only one is need per Citric Acid cycle which means that for every glucose molecule their is double the amount of the Cycle.