The decreasing order of stability of ${\mathrm{O}}_2,{\mathrm{O}}_2^{-},{\mathrm{O}}_2^{+}$ $\mathrm{and}$ ${\mathrm{O}}_2^{2-}$is: 

1. ${\mathrm{O}}_2^{+}>{\mathrm{O}}_2>{\mathrm{O}}_2^{-}>{\mathrm{O}}_2^{2-}$

2. ${\mathrm{O}}_2^{2-}>{\mathrm{O}}_2^{-}>{\mathrm{O}}_2>{\mathrm{O}}_2^{+}$

3. ${\mathrm{O}}_2>{\mathrm{O}}_2^{+}>{\mathrm{O}}_2^{2-}>{\mathrm{O}}_2^{-}$

4. ${\mathrm{O}}_2^{-}>{\mathrm{O}}_2^{2-}>{\mathrm{O}}_2^{+}>{\mathrm{O}}_2$

An electron-deficient compound among the following is:

Which of the following is the most basic oxide?

1. $A{l}_2{O}_3$

2. $S{b}_2{O}_3$

3. $B{i}_2{O}_3$

4. $Se{O}_2$

The number of sigma ($\mathrm{\sigma }$) and pi ($\mathrm{\pi }$) bonds in pent-2-en-4-yne are:

1.  13 $\mathrm{\sigma }$ bonds and no $\mathrm{\pi }$ bond

2.  10 $\mathrm{\sigma }$ bonds and 3 $\mathrm{\pi }$ bonds

3.  8 $\mathrm{\sigma }$ bonds and 5 $\mathrm{\pi }$ bonds

4.  11 $\mathrm{\sigma }$ bonds and 2 $\mathrm{\pi }$ bonds

In piperidine "N" atom has hybridization:

1. sp

2. $s{p}^2$

3. $s{p}^3$

4. $ds{p}^2$

The strongest hydrogen bond present among the following is-

1. $\mathrm{O}—\mathrm{H}‐‐‐\mathrm{S}$

2. $\mathrm{S}—\mathrm{H}‐‐‐\mathrm{O}$

3. $\mathrm{F}—\mathrm{H}‐‐‐\mathrm{F}$

4. $\mathrm{F}—\mathrm{H}‐‐‐\mathrm{O}$

Among the following atomic orbital overlaps, the non-bonding overlap is:
 

1.		2.
3.		4.

A pair in which both species are not likely to exist is:

Combination of atoms A and B that forms an anti-bonding molecular orbital is :

1. $\frac{{\mathrm{\Psi }}_{\mathrm{A}}^2}{{\mathrm{\Psi }}_{\mathrm{B}}^2}$

2. ${\mathrm{\Psi }}_{\mathrm{A}}^2\times {\mathrm{\Psi }}_{\mathrm{B}}^2$

3. ${\mathrm{\Psi }}_{\mathrm{A}}+{\mathrm{\Psi }}_{\mathrm{B}}$

4. ${\mathrm{\Psi }}_{\mathrm{A}}-{\mathrm{\Psi }}_{\mathrm{B}}$