Identify the reagent used in following conversion. Pent -3 -enenitrile…

Identify the reagent used in following conversion. Pent -3 -enenitrile $\stackrel{\mathrm{A}}{\longrightarrow}$ pent -3 - enal
  1. $\mathrm{AlH}(\mathrm{i}-\mathrm{Bu})_2 / \mathrm{H}_3 \mathrm{O}^{+}$
  2. $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7 / \mathrm{H}_2 \mathrm{SO}_4$
  3. $\mathrm{H}_2 / \mathrm{Pd} \cdot \mathrm{BaSO}_4$
  4. $\mathrm{SnCl}_2 \cdot \mathrm{HCl}$

Asked in: MHT CET 2021 (23 Sep Shift 2)

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