2C_6H_5CHO underset(H_2O)overset(OH^-)to C_6H_5CH_2OH + C_6H_5COO^- Which of the following statements are correct regarding the above reduction of benzaldehyde to benzyl alcohol? (i)One hydrogen is coming from H_2O as H^+ and another from C_6H_5CHO as H^- (ii)One hydrogen is coming from H_2O as H^- and another from C_6H_5CHO as H^+ (iii) One hydrogen from H_2O and another from C_6H_5CHO, both in the form of H^- (iv) The reductionis an example of disproportionation reaction

2C_6H_5CHO underset(H_2O)overset(OH^-)to C_6H_5CH_2OH + C_6H_5COO^- W

1.	2C_6H_5CHO underset(H_2O)overset(OH^-)to C_6H_5CH_2OH + C_6H_5COO^- Which of the following statements are correct regarding the above reduction of benzaldehyde to benzyl alcohol? (i)One hydrogen is coming from H_2O as H^+ and another from C_6H_5CHO as H^- (ii)One hydrogen is coming from H_2O as H^- and another from C_6H_5CHO as H^+ (iii) One hydrogen from H_2O and another from C_6H_5CHO, both in the form of H^- (iv) The reductionis an example of disproportionation reaction
Answer» (i),(ii) and (iii) (i) and (iv) (ii),(iii) and (iv) (iii) and (iv) Solution :The hydrogen atom that is added to the CARBONYL carbon of the ALDEHYDE in the REDUCTION is derived DIRECTLY from the other aldehyde molecule as a hydride ion. The second hydrogen that is added to the negatively charged oxygen is coming from the solvent (consult mechanism of Cannizzaro reaction). Oxidation of one molecule of the COMPOUND at the expense of other molecule of the same compound is known as disproportionation.