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Total sum of oxygen atoms and $\pi$-electrons is $3+8=11$
Total number of oxygen atoms $=3$
Total number of $\pi$-bonds $=4$
$\therefore$ Total number of $\pi$-electrons $=8$
$CH _{3} CH _{2} CH = CH _{2}$ $\xrightarrow[{Rh\,\,catalyst}]{{{H_2}/CO}}$