Chemistry

The p-Block Elements.

Question:

Give two examples to show the anomalous behaviour of fluorine.

Answer:

  1. Ionisation enthalpy, electro-negativity and electrode potential are higher for fluorine than the expected trends of other halogen.
  2. Fluorine does not show any positive oxidation state except in HOF.
previuos
next

The p-Block Elements.

Q 1.

Write the reactions of F2 and Cl2 with water.

Q 2.

Match the formulas of oxides given in Column I with the type of oxide given in Column II and mark the correct option.
ncert-exemplar-problems-class-12-chemistry-p-block-elements-47

Q 3.

Can PCl5 act as an oxidising as well as a reducing agent Justify.

Q 4.

Why are halogens coloured?

Q 5.

 Write two uses of ClO2

Q 6.

 Write balanced equations for the following:
(i) NaCl is heated witlrsulphuric acid in the presence of MnO2
(ii) Chlorine gas is passed into a solution of Nal in water.

Q 7.

Match the compounds given in Column I with the hybridization and shape given in Column II and mark the correct option.
ncert-exemplar-problems-class-12-chemistry-p-block-elements-44

Q 8.

 Write the order of thermal stability of the – hydrides of Group 16 elements.

Q 9.

Write a balanced equation for the hydrolytic reaction of PC is in heavy water.

Q 10.

How is the presence of SO2 detected ?

Q 11.

Give the resonating structures of N02 and N2O5.

Q 12.

Write two uses of ClO2

Q 13.

What are the oxidation states of phosphorus in  the following: –
(i) H3PO3 (ii)PCl3
(iii) Ca3P2(iv)Na3PO4
(v) POF3

Q 14.

Write a balanced chemical equation, for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.

Q 15.

 Why is BiH3 the strongest reducing agent amongst all the hydrides of group 15 elements? (C.B.S.E. 2013)

Q 16.

What happens when sulp’hur dioxide is passed through an aqueous solution of Fe(III) salt?

Q 17.

Write the conditions to maximise the yield of H2SO4 by Contact process.

Q 18.

Why is dioxygen a gas but sulphur a solid?

Q 19.

Which one of the following does not exist ?
(i)XeOF4 (ii)NeF2
(iii)XeF4 (iv)XeF6

Q 20.

Reduction potentials of some ions are given below. Arrange them in decreasing order of oxidizing power.
ncert-exemplar-problems-class-12-chemistry-p-block-elements-18

Q 21.

Give reason to explain why ClF3 exists but FCl3 does not exist.

Q 22.

 How is nitrogen prepared in the laboratory? Write the chemical equations of the reactions . involved.

Q 23.

 Why does nitrogen show catenation properties less than phosphorus ? (C.B.S.E. Foreign 2009)

Q 24.

Why is BiH3 the strongest reducing agent amongst all the hydrides of Group 15 elements?

Q 25.

Why is N2 less reactive at room temperature?

Q 26.

List the important sources of sulphur.

Q 27.

Write the order of thermal stability of the – hydrides of Group 16 elements.

Q 28.

Which of the following does not react with oxygen directly?  Zn, Ti, Pt, Fe

Q 29.

How is O3 estimated quantitatively?

Q 30.

Why does NH3 form hydrogen bond but PH3 does not?

Q 31.

Explain why NH3 is basic while BiH3 is only feebly basic.

Q 32.

Nitrogen exists as diatomic molecule and phosphorus as P4. Why?

Q 33.

What inspired N. Bartlett for carrying out reaction between Xe and PtF6?

Q 34.

With what neutral molecule is CIO isoelectronic? Is that molecule a Lewis base?

Q 35.

List the uses of neoirand argon gases.

Q 36.

A brown ring is formed in the ring test for NO3 ion. It is due to the formation of
ncert-exemplar-problems-class-12-chemistry-p-block-elements-10

Q 37.

Which of the following orders are correct as per the properties mentioned against each?
ncert-exemplar-problems-class-12-chemistry-p-block-elements-23

Q 38.

In PCl5, phosphorus is in sp3d hybridised state but all its five bonds are not equivalent. Justify your answer with reason.

Q 39.

SF6 is known but SCl6 is not. Why?

Q 40.

How does ammonia react with a solution of Cu2+?

Q 41.

 What is the covalence of nitrogen in N2O5 ?

Q 42.

 Which of the following does not react with oxygen directly? Zn, Ti, Pt, Fe

Q 43.

Give the reason for bleaching action of Cl2.

Q 44.

Name two poisonous gases which can be prepared from chlorine gas

Q 45.

Discuss the trends in chemical reactivity of group 15 elements.

Q 46.

Illustrate how copper metal can give different products on reaction with HN03.

Q 47.

Give the resonating structures of N02 and N2O5.

Q 48.

The HNH angle value is higher than HPH, H AsH and HSbH angles. Why?
(Hint: Can be explained on the basis of sp3 hybridisation in NH3 and only s-p bonding , between hydrogen and other elements of the group).

Q 49.

Explain why NH3 is basic while BiH3 is only feebly basic.

Q 50.

Give the disproportionation reaction of H3 P03.