Reaction by which benzaldehyde cannot be prepared is
Benzoic acid $\xrightarrow{\mathrm{Zn} \cdot \mathrm{Hg} \text { and conc. } \mathrm{HCl}}$
Toluene $\xrightarrow[\text { (ii) } \mathrm{H}_3 \mathrm{O}^{+}]{\text {(i) } \mathrm{CrO}_2 \mathrm{Cl}_2 \text { in } \mathrm{CS}_2}$
Benzoyl chloride $+\mathrm{H}_2 \xrightarrow[\Delta]{\text { Pd- } \mathrm{BaSO}_4}$
Benzene $+\mathrm{CO}+\mathrm{HCl} \xrightarrow{\text { Anhyd. } \mathrm{AlCl}_3}$
