[FollowTheFez]

Please see attachment for original question and answer (referring to part a. I left b in as it contains needed information).

I can easily identify that the answer is molecule B due to the presence to the Cl (and from the table given in part b, Cl is the only ionised atom). And from calculation molecule B has to have one peak at 172 and another at 174 while molecule has only one peak at 244.

What I don't understand is the 3:1 ratio. What does this even mean? I can't figure out how is ratio was established.

I thought it might have been the ratio of the two peaks. ie. 174:172. But that only reduces to 87:86. I can't see any other way that the ratio could have been made though! Is there any way to figure it out or is it just something that is given and accepted (much like the mass of Carbon is said to be 12)?

[Borek]

I can't figure out how is ratio was established.

It was measured using mass spectrum. There were two signals, one at 174, the other at 172. Their INTENSITIES were 3:1.

[FollowTheFez]

Thank you!