Using an analytical balance, 0.1514 grams of the nickel(II) ammine complex was weighed by difference and placed in an Erlenmeyer flask. Exactly 25 mL of the standardized hydrochloric acid solution was added to neutralize the ammonia in the complex. The excess hydrochloric acid remaining in the Erlenmeyer flask was titrated against the sodium hydroxide. 16.17 mL of sodium hydroxide was required to reach the end point.

How many moles of sodium hydroxide were required?