Which of the following is the least basic?

Which of the following is an example of a symmetrical tertiary amine?

In the following compounds,the order of basicity is as follows:

Which of the following diazonium salts is relatively stable at $0-5 \, ^{\circ}C$?

Arrange the following compounds according to increasing order of boiling points: $n-C_4H_9OH$ $(A)$,$n-C_4H_9NH_2$ $(B)$,$n-C_4H_{10}$ $(C)$,and $C_2H_5NHC_2H_5$ $(D)$.

Identify the product of the following reaction:
$Ph-CH=CH-CN$ $\xrightarrow[2. H_3O^+]{1. CH_3MgBr}$ $\xrightarrow{NaBH_4, \Delta} \text{Product}$