Identify compound $$\mathrm{A}$$ in following reaction

Benzene + Ozone (excess) $$\rightarrow$$ Benzenetriozonide $$\xrightarrow{\mathrm{A}}$$ Glyoxal

Identify the product '$$B$$' in following reaction.

$$2 \mathrm{CH}_3 \mathrm{CHO} \xrightarrow{\text { dil. } \mathrm{NaOH}} \mathrm{A} \xrightarrow[-\mathrm{H}_2 \mathrm{O}]{\Delta} \mathrm{B}$$

Which of the following reagents is used in the reaction shown below?

Benzoyl chloride $$\stackrel{?}{\longrightarrow}$$ Benzaldehyde

Identify the name of following reaction.

Toluene + chromyl chloride $$\stackrel{\mathrm{CS}_2}{\longrightarrow}$$ complex $$\stackrel{\mathrm{H}_3 \mathrm{O}^{+}}{\longrightarrow}$$ Benzaldehyde