# V.B.T. Worksheet

Valence bond Theory (V.B.T) was developed by Walter Heitler and Fritz London in 1927 and was later modified by Linus Pauling to take bond direction into account.

Some of the question related to Valence bond theory are listed below:

Questions:

1. The correct order of decreasing strength of overlapping is:

(a)    s –s > s – p > p – p

(b)   p – p > s – p > s – s

(c)    s – p> p – p > s – s

(d)   s – p > s – s > p – p

2. when Z-axis is molecular axis then $\pi$-molecular orbitals are formed by the overlapping of:

(a)    $s + p_z$

(b)    $p_x + p_x$

(c)    $p_x + p_y$

(d)   $p_z + p_z$

3. The bond order for $O^{+2}_2$ is:

(a)    2

(b)   2.5

(c)    3

(d)   1

4. The bond length of $H^-_2, H_2^+, H_2$ is in order:

(a)    $H^-_2 > H_2^+ > H_2$

(b)   $H_2 > H_2^ - > H_2^+$

(c)    $H^+_2 > H_2^- > H_2$

(d)   $H^+_2 > H_2 > H^-_2$

5.  Which is diamagnetic here?

(a)    $O^+_2$

(b)   $NO^+$

(c)    $O_2$

(d)   NO

6.  During the formation of $N^+_2 \text{from} N_2 \text{the} e^-$ is removed from:

(a)    $\sigma$ orbital

(b)   $\pi$ orbital

(c)    $\overset{*}{\sigma}$ orbital

(d)   $\overset{^*}{\pi}$ orbital