In Gattermann reaction, a diazonium group is replaced by $\underline{\mathrm{X}}$ using $\underline{\mathrm{Y}}$. $\underline{\mathrm{X}}$ and $\underline{\mathrm{Y}}$ are

• Correct answer
  A

  $\underline{X}$ - $\mathrm{Cl}^{\ominus}$, $\underline{Y}$ - $\mathrm{Cu} / \mathrm{HCl}$
• B

  $\underline{X}$ - $\mathrm{Cl}^{\oplus}$, $\underline{Y}$ - $\mathrm{CuCl}_{2} / \mathrm{HCl}$
• C

  $\underline{X}$ - $\mathrm{Cl}^{\ominus}$, $\underline{Y}$ - $\mathrm{CuCl}_{2} / \mathrm{HCl}$
• D

  $\underline{X}$ - $\mathrm{Cl}_{2}$ , $\underline{Y}$ - $\mathrm{Cu}_{2} \mathrm{O} / \mathrm{HCl}$

Hence, the correct answer is option: 'A'.