Aldehydes and ketones having at least one α-hydrogen undergo aldol condensation. The compounds (ii) 2−methylpentanal, (v) cyclohexanone, (vi) 1-phenylpropanone, and (vii) phenylacetaldehyde contain one or more α-hydrogen atoms. Therefore, these undergo aldol condensation.

Aldehydes having no α-hydrogen atoms undergo Cannizzaro reactions. The compounds (i) Methanal, (iii) Benzaldehyde, and (ix) 2, 2-dimethylbutanal do not have any α-hydrogen. Therefore, these undergo Cannizzaro reactions.

Compound (iv) Benzophenone is a ketone having no α-hydrogen atom and compound (viii) Butan-1-ol is an alcohol. Hence, these compounds do not undergo either aldol condensation or Cannizzaro reactions.

Step 2:

The aldol condensation products are as follows:
a. 2−Methylpentanal

b. Cyclohexanone,

c.
1-Phenylpropanone

d.
Phenyl acetaldehyde


Step 3:

The compound that gives the Cannizzaro reaction is as follows:

Cannizzaro reaction
a. 
Methanal

b.
Benzaldehyde

c.
2, 2-dimethylbutanal

Step 4:

The structure does not show either aldol condensation or cannizarro reaction are as follows:

Butan-1-ol and Benzophenone. 

The structures are as follows: