The spectrum below contains C H and what other atom out of t

The spectrum below contains C, H, and what other atom out of the list? Why?

A) N

B) Cl

C) Br

D) S

E) O

100 - MS-NU-3296 Relative Intensity 8 3 20 - Omtrtfmmtihamfettfrymttttttttttttttttmmttntifmptifimmrhymmtttttrmmmmmmmmmmmmmmmlfter 50 75 75 100 150 m/z 25 125

Solution

Answer is option C. Br

Reason : when bromine is present in the compound, the molecular ion peak will appear as M and M+2 in equal intensity, since the naturally occuring Br-79 and Br-81 isotope present in equal ratio.

In above compound molecular ion peak appear at 149 and 151 m/z in equal intensity ratio, this show the presence of bromine