Chemistry

The p-Block Elements.

Question:

Assertion (A): SF6 cannot be hydrolysed but SF4 can be.
Reason (R): Six F atoms in SF6 prevent the attack of H2O on sulphur atom of SF6.

Answer:

(a) SF6 is sterically protected due to presence of six F atoms around S which prevents the attack of H2O on SF6.

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.

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

Q 4.

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

Q 5.

Why are halogens coloured?

Q 6.

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 7.

 Write two uses of ClO2

Q 8.

 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 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.

Assertion (A): Both rhombic and monoclinic sulphur exist as S8 but oxygen exists as OÏ€.
Reason (R): Oxygen forms pπ-pπ multiple bond due to small size and small bond length but pπ-pπ bonding is not possible in sulphur.

Q 16.

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

Q 17.

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

Q 18.

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

Q 19.

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

Q 20.

Why is dioxygen a gas but sulphur a solid?

Q 21.

How is O3 estimated quantitatively?

Q 22.

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

Q 23.

List the uses of neoirand argon gases.

Q 24.

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 25.

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 26.

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

Q 27.

How does ammonia react with a solution of Cu2+?

Q 28.

 What is the covalence of nitrogen in N2O5 ?

Q 29.

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

Q 30.

Why does NH3 form hydrogen bond but PH3 does not?

Q 31.

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

Q 32.

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 33.

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

Q 34.

Explain why fluorine forms only one oxoacid, HOF.

Q 35.

Explain why inspite of nearly the same electronegativity, nitrogen forms hydrogen bonding while chlorine does not.

Q 36.

 List the uses of neoirand argon gases.

Q 37.

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

Q 38.

Why is N2 less reactive at room temperature?

Q 39.

Mention the conditions required to maximise the yield of ammonia.

Q 40.

What happens when white phosphorus is heated with concentrated NaOH solution in an inert atmosphere of CO2 ?

Q 41.

List the important sources of sulphur.

Q 42.

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

Q 43.

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

Q 44.

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

Q 45.

Comment on the nature of two S-O bonds formed in S02 molecule. Are the two S-O bonds in this molecule equal ?

Q 46.

Mention three areas in which H2SO4 plays an important role.

Q 47.

Why does NH3 form hydrogen bond but PH3 does not?

Q 48.

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

Q 49.

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

Q 50.

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