A Pure Sample of Tritium, ³H, Was Prepared and Sealed

Multiple Choice

A pure sample of tritium, ³H, was prepared and sealed in a container for a number of years. Tritium undergoes β decay with a half-life of 12.32 years. How long has the container been sealed if analysis of the contents shows there are 5.25 mol of ³H and 6.35 mol of ³He present?

A) 2.34 y
B) 3.38 y
C) 9.77 y
D) 14.1 y
E) 25.6 y