Nitrogen exists as a diatomic molecule and phosphorus as P₄ because on moving 

1.	up a group, the tendency to form pπ−pπ bonds decreases.
2.	down a group, the tendency to form pπ−pπ bonds decreases.
3.	down a group, the tendency to form dπ−dπ bonds decreases.
4.	up a group, the tendency to form dπ−dπ bonds decreases.

A chemical that depletes the ozone layer is:

1. Sulphur

2. Chlorofluorocarbons (CFCs)

3. Nitrogen

4. Hydrogen

Fluorine forms only one oxoacid, HOF because of -

1. Low electronegativity and small size

2. High electronegativity and small size

3. High electronegativity and big size

4. Low electronegativity and big size

Oxygen forms hydrogen bonds while chlorine does not, because :

The uses of ${\mathrm{ClO}}_2$ is /are-

1. It is used for purifying water

2. It is used as a bleaching agent

3. Both '1'and '2'

4. None of the above

Halogens are colored because -

1. They absorb radiations in the U.V region

2. They absorb radiations in the visible region

3. They absorb radiations in the infrared region

4. They absorb radiations in the radiowaves region

 4HCl + O₂ →  X + 2H₂O

Cl₂ + H₂O → HCl  + Y ;

X and Y in the above reaction are respectively:

1.  Cl₂ , HOCl

2. HOCl ,Cl₂

3. HClO₃, HOCl

4. HOCl, HClO₄

A neutral molecule that is isoelectronic with ClO^- is -

1. ClF which is a Lewis base

2. ClF which is a Lewis acid

3. HCl which is a Lewis base

4. HCl which is a Lewis acid

The correct statement(s) regarding group 15 elements is(are):

The main product(s) formed in the given reaction is/are:

${\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)+{\mathrm{NaNO}}_2\left(\mathrm{aq}\right)\to ....+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+\mathrm{NaCl}\left(\mathrm{aq}\right)$

$1.<mspace\; width="1em"></mspace>{\mathrm{NH}}_3$
$2.<mspace\; width="1em"></mspace>{\mathrm{N}}_2$
$3.<mspace\; width="1em"></mspace>{\mathrm{N}}_2{\mathrm{H}}_4$
$4.<mspace\; width="1em"></mspace>\mathrm{Both}<mspace\; width="1em"></mspace>\left(1\right)\hspace{0.17em}\mathrm{and}\left(3\right)$