Question

The X -X bond length is 1.5 $\stackrel{\circ }{A}$ and Y - Y bond length is $2.54\stackrel{\circ }{A}$. If electronegativities of 'X' and 'Y' are 3.5 and 2.0 respectively, the X - Y bond length is likely to be

• A. $2.02\stackrel{\circ }{A}$
• B. $1.44\stackrel{\circ }{A}$
• C. $2.88\stackrel{\circ }{A}$
• D. $1.88\stackrel{\circ }{A}$

Answer 1

The correct option is D $1.88\stackrel{\circ }{A}$

Atomic radius of
$X=\frac{\text{Bond length}}{2}=\frac{1.5}{2}=0.75\stackrel{\circ }{A}$
Atomic radius of $Y=\frac{2.54}{2}=1.27\stackrel{\circ }{A}$
Hence,
using Stevenson equation, X - Y bond length = 0.75 + 1.27 - 0.09 $\times$ (3.5-2) $=1.88\stackrel{\circ }{A}$