Question

The increasing order of $pK_{b}$ values of the following compounds is -

• A. $I < II < IV < III$
• B. $II < IV < III < I$
• C. $II < I < III < IV$
• D. $I < II < III < IV$

Answer 1

Answer: (A)

Basic strength $\alpha K _{ b } \alpha \frac{1}{ pK _{ b }}$

B.S. $\alpha+ M ,+ H ,+ I \alpha \frac{1}{- M ,- H ,- I }$

B.S. order $\Rightarrow I > II > I V > III$

$pK _{ b }$ order $\Rightarrow III > IV > II > I$