Chapter 14, Problem 62ASP

Can I please get help with this? And can I please the lowest possible significant number?

What is the molar mass of a gas that takes three times longer to effuse than helium?

First image: I have to show the mecanism (with arows and structures) of the reaction at the bottom. Also I have to show by mecanism why the reaction wouldn't work if the alcohol was primary Second image: I have to show the mecanism (with arrows and structures) for the reaction on the left, where the alcohol A is added fast in one portion its not an exam