Q8 · 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
\[ \begin{array}{l} \text{Diethyl-phthalate} \rightarrow \mathrm{F_1^{+}} \rightarrow \mathrm{F_2^{+}} + \mathrm{CO} \\ \qquad\; (\mathrm{M^{+}} = 222) \qquad\qquad (177) \end{array} \]
(a)141.2
(b)125.4
(c)45.0
(d)210.2
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
F₂⁺ = 177 − 28 = 149; metastable peak m* = m₂²/m₁ = 149²/177 = 125.4 (b).
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