Which of the following molecules does not exist?

1. $O{F}_2$

2. $O{F}_4$

3. $S{F}_2$

4. $S{F}_4$

The species having no p$\mathrm{\pi }$-p$\mathrm{\pi }$ bond but has a bond order equal to that of $O_2$

(a) $CIO\underset{3}{-}$     

(b) $P{O_4}^{3-}$   

(c)$S{O_4}^{2-}$   

(d) $Xe{O}_3$

Select the pair of elements expected to form the strongest ionic interaction.

1.  Al and As

2.  Al and N

3.  Al and Se

4. Al and O

The correct order of increasing s-character (in percentage) in the hybrid orbitals of the following molecules/ions is:

How many possible resonance forms exist for the nitrate ion, \(\text{NO}_3^-\)​?

Which of the following molecule will have all equal $\mathrm{X}—\mathrm{F}$ bond length? (where X= central atom)

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Which of the following fact is directly explained by the statement 'oxygen is a smaller atom than sulpher'?

(1) $H_{2}O$ boils at a much higher tempreture than $H_{2}S$

(2) $H_{2}S$ undergoes intermolecure hydrogen bonding

(3) $H_{2}O$ is liquid and $H_{2}S$ is gas at room tempreture 

(4) S$—$H bond is longer than O$—$H bond

Among given species identify the isostructural pairs:

(1) $\left[N{F}_{3<mspace\; width="1em"></mspace>}<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>B{F}_3\right]$

(2) $\left[B{F_4}^{-}<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>N{H_4}^{+}\right]$

(3) $\left[BC{l}_3<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>BrC{l}_3\right]$

(4) $\left[N{H}_3<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>N{O_3}^{-}\right]$

In which of the following cases $\mathrm{C}—\mathrm{C}$ bond length will be highest?

(1) ${\mathrm{CH}}_3—{\mathrm{CF}}_3$                               (2) ${\mathrm{FCH}}_2—{\mathrm{CH}}_2\mathrm{F}$

(3) ${\mathrm{F}}_2\mathrm{CH}-{\mathrm{F}}_2\mathrm{CH}$                            (4) ${\mathrm{CF}}_3—{\mathrm{CF}}_3$

Determine the ratio of σ-bonds to π-bonds in tetracyanoethene, (NC)₂C=C(CN)₂.

1.  2:1

2.  1:1

3.  1:2 

4.  None of the above