VOICE 4. Chemical Equilibrium The left flask contains iodine molecules made up of nonradioactive isotopes 1-127, while the right flask contains iodine molecules made up of radioactive isotopes 1-131. 126) 12(e) When the stop cock is closed, See the radiation Counter and answer the following questions. a-what evidence shows that left flask contains nonradioactive isotopes 1-127? 02 b-what evidence shows that right flask contains radioactive isotopes 1-131? When the stop cock is opened, See the radiation Counter and answer the following questions. c-What are the measurement of radioactive counter in both flasks? d- What we call constant reading in both radiation detectors