A radioactive mixture contains two α-emitting species X and Y with half lives of 5 min and 50 hours respectively. At a given instant the mixture emits 8000 α-particles per minute, and 5 minutes later

Question

A radioactive mixture contains two α-emitting species X and Y with half lives of 5 min and 50 hours respectively. At a given instant the mixture emits 8000 α-particles per minute, and 5 minutes later it emits 5500 particles per minute. The ratio of activities of X : Y in the initial mixture was

TestHub · Accepted Answer

Let initial activities be a (X) and b (Y): a + b = 8000.

In 5 min X halves. Y has half-life 50 h = 3000 min, so it barely decays in 5 min.

a/2 + b = 5500. Subtract: a/2 = 2500, so a = 5000 and b = 3000.

X : Y = 5 : 3.

Answer: (C).

Chemistry - Chemical Kinetics Question with Solution | TestHub

Options:

Doubts & Discussion