The number of unpaired electrons in a paramagnetic diatomic molecule of an element with atomic mass 16 is :

1. 2

2. 3

3. 4

4. 1

Which of the following is not isostructural with SiCl₄?

(a) SCl₄            (b) ${\mathrm{SO}}_4^{2-}$               (c) ${\mathrm{PO}}_4^{3-}$                 (d) ${\mathrm{NH}}_4^{+}$

Least stable hydride is:

(1) stannane 

(2) silane 

(3)  plumbane 

(4) germane

Correct order of strength of H-bond in the following compounds is : 

(1) $H_{2}O > H_2{O}_2 > HF > H_{2}S$ 

(2) $HF \ge H_2{O}_2 > H_{2}O > H_{2}S$

(3) $HF >\hspace{0.17em}{H}_{2}O > H_{2}S > H_2{O}_2$

(4) $HF >\hspace{0.17em}{H}_2{O}_2 > H_{2}O > H_{2}S$

Molecule having non-polar as well as polar bonds but the molecule as a whole is polar:

(a) $S_2{F}_2$

(b) ${\mathrm{N}}_2{\mathrm{O}}_4$

(c) ${\mathrm{Si}}_2{\mathrm{H}}_6$                                           

(d) ${\mathrm{I}}_2{\mathrm{Cl}}_6$

Choose the correct statement regarding $SeOC{l}_2$ molecule:

1. It does not contain a plane of symmetry

2. $\text{'}\mathrm{Cl}-\widehat{\mathrm{Se}}-\mathrm{Cl}\text{'} \mathrm{bond} \mathrm{is} \mathrm{greater} \mathrm{than} \text{'}\mathrm{Cl}-\widehat{\mathrm{Se}}-\mathrm{O}\text{'} \mathrm{bond} \mathrm{angle}$

3. Lone pair has greater than 33.3% s-character

4.  Central atom used one d-orbital in bonding.

Which of the following compounds can form H-bonding with each other? 

(a) $C{H}_3 COOH and H_{2}O$

(b) Phenol and $C{H}_4$

(c) $CH{F}_3 and acetone$

(d) $P{H}_{3 }and HF$

Which of the following compound is planar and non-polar?

(1) $Xe O_4$

(2) $S{f}_4$

(3) $Xe f_4$

(4) $C{f}_4$

The incorrect statement(s) regarding ${\mathrm{CX}}_3$ species is:

(1) If electronegativity of surrounding element 'X' is less than 2.5, then central carbon atom used almost 33% s-character in their hybrid bonding orbitals

(2) If electronegativity of surrounding element 'X' is more than 2.5, then central carbon atom used almost 25% s-character in their hybrid bonding orbitals

(3) If 'X' is 'F', then species should be polar and pyramidal

(4) If 'X' is H, then species should be polar and planar

$H_{2}O$ has a net dipole moment while Be$F_2$ has zero dipole moment because :

(1) F is more electronegativity than oxygen 

(2) Be is more electronegativity than oxygen 

(3) $H_{2}O$ molecule is linear and Be$F_2$ is bent 

(4) $Be{F}_2$ molecule is linear and $H_{2}O$ is bent