Section A
Q1. Answer the following questions :
(a) In the Cannizzaro reaction of benzaldehyde, suggest a suitable method to know the source of second hydrogen that becomes attached to benzyl alcohol, i.e., if it comes from solvent (H2O) or from a second molecule of benzaldehyde.
(b)
Neopentyl-type bromide (I) undergoes rearrangement during SN 1 hydrolysis, but no such rearrangement takes place with its phenyl analogue (II). Explain :
\beginarrayccc & \textif & \textif \\ \mid & | & \textif \\ \textMe - \textC-\textCH \text--- \textMe & & \textMe - \textC-\textCH \text--- \textPh \\ & & | & \textif \\ \textMe - \textBr & & \textMe - \textBr \\ \endarray
(I) (II)
(c)
Which of the following compounds has the greater dipole moment? Justify your answer:
A
B
(d) Methyl radical (CH3) is planar, while trifluoromethyl radical (CF3) is pyramidal. Justify.
(e)
Indicate what types of sigmatropic reactions are involved in the following transformations :
CH3
CH3
CH3
CH3
Heat
CH3
CH3
CH3
CH3
CH3
CH3
CH3
CH3
(f)
How will you prepare the following compound by Skraup synthesis? Give mechanism for its formation :
\rm H3CO
\mathbf2
