Which from following reactions exhibits good atom economy according to the principles of green chemistry?

Which from following reactions exhibits good atom economy according to the principles of green chemistry?
  1. $\begin{aligned} & \mathrm{C}_4 \mathrm{H}_9 \mathrm{OH}+\mathrm{NaBr}+\mathrm{H}_2 \mathrm{SO}_4 \longrightarrow \\ & \mathrm{C}_4 \mathrm{H}_9 \mathrm{Br}+\mathrm{NaHSO}_4+\mathrm{H}_2 \mathrm{O}\end{aligned}$
  2. $\mathrm{C}_2 \mathrm{H}_4+\mathrm{H}_2 \xrightarrow{\mathrm{Ni}} \mathrm{C}_2 \mathrm{H}_6$
  3. $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}+\mathrm{C}_2 \mathrm{H}_5 \mathrm{COOH} \longrightarrow \mathrm{C}_2 \mathrm{H}_5 \mathrm{COOC}_2 \mathrm{H}_5+\mathrm{H}_2 \mathrm{O}$
  4. $\begin{aligned} & \mathrm{C}_4 \mathrm{H}_9 \mathrm{OH}+\mathrm{SOCl}_2 \xrightarrow{\Delta} \mathrm{C}_4 \mathrm{H}_9 \mathrm{Cl}+\mathrm{HCl}+ \\ & \mathrm{SO}_2\end{aligned}$

Solution

$\begin{aligned} & \mathrm{C}_2 \mathrm{H}_4+\mathrm{H}_2 \xrightarrow{\mathrm{Ni}} \mathrm{C}_2 \mathrm{H}_6 \\ & \text { Atom economy }=\frac{\text { Mol. wt of } \mathrm{C}_2 \mathrm{H}_6}{\text { Mol.wt of }\left(\mathrm{C}_2 \mathrm{H}_4+\mathrm{H}_2\right)} \times 100 \\ & =\frac{30}{30} \times 100=100 \%\end{aligned}$

Asked in: MHT CET 2024 (10 May Shift 2)

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