Q78 · CSIR NET Chemistry, December 2014
Paper: CSIR NET December 2014 · Subject: Organic Chemistry · Chapter: Organic Spectroscopy · Topic: Mass Spec · Marks: 2 · Difficulty: Medium
The mass of metastable ion produced due to decomposition of $\mathrm{F}_{1}{ }^{+}$ in the following mass fragmentation sequence is
\[ \begin{array}{ccc} \text{Diethyl-phthalate} \rightarrow & \mathrm{F}_{1}{ }^{+} \rightarrow & \mathrm{F}_{2}{ }^{+}+\mathrm{CO} \\ & (\mathrm{M}+222) & (177) \end{array} \]
(a)141.2
(b)125.4
(c)45.0
(d)210.2
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
m* = 149²/177 = 125.4 (b).
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