In a first order reaction A---> B the ratio of molar concentration of A and B in the reaction mixture after 100 minute is 1:3. What would be the time needed from the start to have them in the ratio of 1:1?

1 Answer
Mar 9, 2018

I don't see how this is even physically possible. If the mol ratio of A to B is 1:1, and this reaction is irreversible AS-WRITTEN, you can never have more B than A unless B was manually added, or the reaction goes backwards...

If you really mean 3:1, then the start of the reaction had a 4:0 "ratio", and 100 minutes later, "1 mol" of A reacts to make "1 mol" of B, giving 3:1... Then 100 minutes later, "1 mol" of A reacts again to make "1 mol" of B, giving the 2:2 ratio.