Important Questions Chemistry Class XII

11/29/2011 CBSE

Q. 1. There is a considerable increase in covalent radius from N to P but from
As to Bi only a small change is observed.

 

 Q. 2. Ionisation enthalpy of group 15 elements is much higher than that of
group 14 elements.

 

 Q. 3. Ionic radius of Sb and Bi are very less when compared to the ionic
radius of N,P and As.

 

 Q. 4. Metallic character of group 15 elements decreases on going down the
group.

 

 Q. 5. Tendency to show – 3 oxidation states in group 15 decreases on
going down the group.

 

 Q. 6. Nitrogen can’t form penta halides.

 

 Q. 7. Nitrogen exhibits bonding while heavier members exhibit bonding.

 

 Q. 8. N2 is a gas while P4 is a solid.

 

 Q. 9. Catenation tendency is weaker in nitrogen.

 

 Q. 10. N2 molecule is chemically inert while white phosphorus is more
reactive.

 

 Q. 11. In group 15, +3 oxidation state is more stable than +5 oxidation
state on going down the group .

 

 Q. 12. R3 P=O is known but R3 N=O is unknown.

 

 Q. 13. Basicity of hydrides NH3> PH3 > AsH3 > SbH3 > BiH3

 

 Q. 14. Stability of hydrides NH3> PH3 > AsH3 > SbH3 > BiH3

 

 Q. 15. Reducing character of hydrides NH3<>3 <>3 <>3 3

 

 Q. 16. The oxides in higher oxidation states of group 15 elements are more
acidic than that of lower oxidation state.

 

 Q. 17. Basicity of group 15 oxides increases on going down the group.

 

 Q. 18. PCl5 is more covalent than PCl3.

 

 Q. 19. PCl5 is more covalent than PF5.

 

 Q. 20. All the five bonds in PCl5 are not equivalent.(Or) PCl5 is more
reactive than PCl3.

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