In X- H ----- Y, X, and Y both are electronegative elements. The correct statement among the following is:

1.	Electron density on X will increase and on H will decrease.
2.	In both electron density will increase.
3.	In both electron density will decrease.
4.	On X electron density will decrease and on H increases.

Find the reason why nitrogen exists as N₂, whereas phosphorus exists as P₄.

1. Presence of a triple bond between phosphorus atoms
2. $\mathrm{Weak\; p\pi –p\pi \; bonding\; in\; phosphorus}$

3. $\mathrm{Strong\; p\pi –p\pi \; bonding\; in\; phosphorus}$
 
4. Multiple bonds easily form in phosphorus

NH₃ forms a hydrogen bond but PH₃ does not because:  

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

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