Group 15 p Block Important Questions

Group – 15 Elements

1 MARK QUESTIONS

1.





Which one of  PCl4 and PCl4 is not likely to exist and why? [Delhi 2012]

2.

Complete the following chemical reaction equation:

P4

+

SO2Cl2



[Delhi 2012] 3.

Draw the structure of the following Molecule : H3 PO2 [Delhi 2012; All India 2012, 2009]

4.

Explain the following : The chemical reactivity of nitrogen is much less than that of phosphorus. [Foreign 2012; All India 2012; Delhi 2009, 2008C]

5.

Which is a stronger reducing agent, SbH3 or

BiH3 and why?

[All India 2012, 2011] 6.

NF3

is an exothermic compound whereas NCl3 is not. [All India 2012, 2011; Delhi 2011, 2011, 2010]

7.

Draw the molecular structure of  N 2 O5 . [All India 2012, 2009]

8.

Complete the following equation Cu + HNO3 (dilute)  [All India 2012; Foreign 2009]

9.

Phosphorus has' greater tendency for catenation than nitrogen. [All India 2012]

10.

What is the basicity of  H3 PO2 and why? [All India 2012]

2

Group – 15 Elements

11.

The N—O bond in



NO 2

is shorter than the N —O bond in NO3 . 

[Delhi 2011; All India 2011] 12.

All the P— Cl bonds in PCl5 , molecule are not equivalent [Delhi 2011; All India 2009, 2006C; Foreign 2006]

13.

Complete the following chemical equation. [Delhi 2011, 2010; Foreign 2011, 2010] P4



NaOH



H 2O 

OR P4

14.



SO2Cl2



Tendency to form pent halides decreases down the group in group 15 of the Periodic Table. [Delhi 2011]

15.

Complete the following chemical equation : [Delhi 2011] l2

16.



HNO3 (conc.) 

Draw the structure of  HPO3 3 and why? [All India 2011, 2009; All India 2009C]

17.

Complete the following chemical equations. [Foreign 2012, 2011, 2010, 2009 All India 2011, 2009] HgCl2 + PH 3

18.



What is the basicity of  H3 PO3 and why? [All India 2011]

3

Group – 15 Elements

19.

Mention optimum conditions for the Industrial manufacture of ammonia by Haber's process. [Foreign 2011; All India 2008]

20.

Red phosphorus is less reactive than white phosphorus. Why? [Foreign 2011; AB India 2008]

21.

Draw the structure of  NF3 and  H 3 PO3 molecules. [Foreign 2011]

22.

Nitrogen does not form penthalides. [All India 20HC, 2009; Delhi 2010; 2008C]

23.

Ammonia is more basic than phosphine. [All India 2011C; Delhi 2010, 2009, 2008]

24.

NH3 acts as a good ligand.

[Delhi 2011C] 25.

BiCl3 is less covalent than

PCl3 .

[Delhi 2011C] 26.

Why does NO2 dimerise? [Delhi 2010]

27.

The stability of + 5 oxidation state decreases down the group in group 15 of the Periodic Table. [Delhi 2010; Foreign 2009]

28.

Solid phosphorus pent chloride behaves as an ionic compound. [Delhi 2010, 2010C]

4

Group – 15 Elements

29.

Draw the structure of  H 4 P2 O7 . [Delhi 2010]

30.

The stability of +3 state increases down the group in group 15 of the Periodic Table [Foreign 2010, 2009]

31.

Complete the following chemical reaction equations [Foreign 2010] AgCl (s) + NH3 (aq)

32.



Arrange the following in order of the increasing basic strength. [Delhi 2010, 2009C] PH 3 , NH3 , SbH3 ,

33.

AsH3

Draw the structure and predict the shape of  H3 PO3 . [Delhi 2010C; All India 2006]

34.

N 2 is not particularly reactive, explain.

[Delhi 2010C] 35.

What is the covalence of nitrogen in

N 2 O5 ?

[All India 2010C] 36.

What happens when H3 PO3 (orthophosphorous acid) is heated? [All India 2011C]

37.

Nitrogen shows weaker tendency for Catenation than phosphorus. [All India 2010C, 2009; Foreign 2009]

38.

Complete the following chemical reaction equations. [Delhi 2009; Foreign 2009] 5

Group – 15 Elements P4 (

39.

is) + NaOH (aq) + H 2 O (I)



In the structure of  HNO3 molecule, the N —O bond (121 pm) is shorter than N —OH bond (140 pm). [Delhi 2009; All India 2009]

40.

Draw the structure of  PCl5 (s). [All India 2009, 2008]

41.

Ammonia has higher boiling point than phosphine. [All India 2009]

42.

Bi (V) is a stronger oxidizing agent than Sb (V). [All India 2009, 2008; Delhi 2006C]

43.

Complete the following reaction equation [Foreign 2009] PCl5 + H 2 O (excess)

44.



Give reason : PH 3 is a weaker base than NH3 [Delhi 2009C]

45.

Give reason: In the solid state, PCl5 behaves as an ionic species. [Delhi 2009C, 2006]

46.

The basic character of the hydrides of group 15 elements decreases with increasing B atomic numbers. [All India 2009]

47.

Complete the following reactions : [All India 2009] NH3 + NaOCI

48.



Write chemical equation for the following process : Orthophosphous acid is heated [Delhi 2008] 6

Group – 15 Elements

49.

Complete the following chemical equation : [Delhi 2008] Cu 2 (aq) + NH3 (aq) 

50.



Complete the following chemical equation : [Delhi 2008, 2006] Ca3 P2 (s )  H 2O(l ) 

51.

Why the bond angle in is PH3 is lesser than that in NH3 molecule? [All India 2008]

52.

Ammonia has greater affinity for protons than phosphine( PH 3 ) [All India 2008]

53.

What happens when white phosphorus heated with cone, atmosphere?

NaOH solution in an inert gas

[All India 2008C] 54.

(i)

Write the reaction of thermal decomposition of sodium azide .

(ii)

What happens when PCI5 is healed? [Delhi 2007]

55.

How does ammonia react with a solution of  Cu 2 ? 

[All India 2007] 56.

H3 PO2 acts as a monobasic acid. Give reason.

[Foreign 2007; All India 2006] 57.

Nitric oxide becomes brown when released in air, why? [Delhi 2006]

7

Group – 15 Elements

58.

Write the chemical equations involved in the preparation of the H3 PO3 . [All India 2006]

59.

Concentrated nitric acid turns yellow on exposure to sunlight, why? [Foreign 2006]

60.

H3 PO3 is a diprotic acid. Give reason.

[Delhi 2006C] 2 MARKS QUESTIONS

61.

Explain the following observations: (i)

The molecules

(ii)

All the bonds in PCI5 molecule are no equivalent.

NH 3

and

NF3 have dipole moments which are of opposite direction.

[Delhi 2012] 62.

Draw the structures of white phosphorus and red phosphorus. Which one of these two types of  phosphorus is more reactive and why? [Delhi 2010]

63.

Complete the following chemical reaction equations : [All India 2010]

64.

(i)

I2

+ conc. HNO3

(ii)

HgCl2 + PH3

(i)

PH 3 has lower boiling point Than NH3 , why?





[Delhi 2007] (ii)

Write balance equation, when ammonia is dissolved in water. [Delhi 2007]

65.

State the difference in properties of white and red phosphorus. [All India 2006C]

8

Group – 15 Elements

3 MARKS QUESTIONS

66.

Explain each of the following : (i)

Nitrogen is much less reactive that phosphorus.

(ii)

The stability of +5 oxidation state decreases down group 15.

(iii)

The bond angles (O—N—O) are not of the same value in



NO 2

and



NO 2

. [Delhi 2012]

5 MARKS QUESTIONS

67.

How is ammonia manufactured industrially? Draw flow chart for the manufacture of ammonia. Give any two uses. [All India 2007]

68.

(i)

Explain the Ostwald’s process to manufacture nitric acid.

[Delhi 2006C] (ii)

Write the balanced reaction when nitric acid react with (a) I 2 (b) C (c)

(iii)

S8

(d)

P4

Give any two uses.

9