Question

The decreasing order of -I effect of the orbitals is :
I. $sp$

II. $s{p}^2$

III. $s{p}^3$

• A. $I>II>III$
• B. $III>II>I$
• C. $I>III>II$
• D. $II>III>I$

Answer 1

The correct option is A $I>II>III$

The more the percentage $s$ character, the more is the penetration effect of $s$ orbital towards the nucleus
, and hence more electron-withdrawing effect. So, the decreasing order of -I effect of orbitals is $sp$ (50% $s$) > $s{p}^2$ (33% $s$) > $s{p}^3$ (25% $s$).