Chemistry

The p-Block Elements.

Question:

Match the items of Column I and Column II and mark the correct option.
ncert-exemplar-problems-class-12-chemistry-p-block-elements-53

Answer:

ncert-exemplar-problems-class-12-chemistry-p-block-elements-54

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The p-Block Elements.

Q 1.

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

Q 2.

What is the basicity of H3PO4?

Q 3.

Why does NH3 form hydrogen bond but PH3 does not?

Q 4.

Justify the placement of O, S, Se, Te and Po in the same group’of the periodic table in terms of electronic configuration, oxidation state and hydride formation.

Q 5.

How is the presence of SO2 detected ?

Q 6.

Why does NH3 form hydrogen bond but PH3 does not?

Q 7.

Why does nitrogen show catenation properties less than phosphorus?

Q 8.

SF6 is known but SCl6 is not. Why?

Q 9.

PCl5 reacts with finely divided silver on heating and a white silver salt is obtained, which dissolves on adding excess aqueous NH3 solution. Write the reactions involved to explain what happens.

Q 10.

Why is ICI more reactive than l2?

Q 11.

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

Q 12.

How is ammonia manufactured industrially?

Q 13.

 Why are halogens strong oxidising agents?

Q 14.

Why is N2 less reactive at room temperature?

Q 15.

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

Q 16.

Complete the following reactions:
(i)C2H2  + O2 -> (ii) 4Al + 3 O2 ->

Q 17.

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

Q 18.

Explain why fluorine forms only one oxoacid, HOF.

Q 19.

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

Q 20.

Arrange the following in the order of property  indicated for each set: –
(i) F2 , Cl2 , Br2 , I2 – increasing bond dissociation enthalpy.
(ii) HF, HCI, HBr, HI – increasing acid . strength.
(iii) NH3, PH3, AsH3, SbH3, BiH3 – increasing Sol. base strength.

Q 21.

On heating ammonium dichromate and barium azide separately we get
(a) N2 in both cases
(b) N2 with ammonium dichromate and NO with barium azide
(c) N2O  with ammonium dichromate and N2 with barium azide
(d) N2O with ammonium dichromate and N2O with barium azide

Q 22.

Match the items of Column I and Column II and mark the correct option.
ncert-exemplar-problems-class-12-chemistry-p-block-elements-49
ncert-exemplar-problems-class-12-chemistry-p-block-elements-50

Q 23.

Assertion (A): HNO3 makes from passive.
Reason (R): HNO3 forms a protective layer of ferric nitrate on the surface of iron.

Q 24.

Assertion (A): HI cannot be prepared by the reaction of KI with concentrated H2SO4.
Reason (R): HI has lowest H – X bond strength among halogen acids.

Q 25.

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.

Q 26.

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

Q 27.

Why is H2O a liquid and H2S a gas?

Q 28.

Give two examples to show the anomalous behaviour of fluorine.

Q 29.

Give the resonating structures of N02 and N2O5.

Q 30.

 How is SO2 an air pollutant?

Q 31.

 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 32.

 Arrange the following in the order of property indicated for each set: –
(i) F2 , Cl2 , Br2 , I2 – increasing bond dissociation enthalpy.
(ii) HF, HCI, HBr, HI – increasing acid . strength.
(iii) NH3, PH3, AsH3, SbH3, BiH3 – increasing Sol. base strength.

Q 33.

 List the uses of neoirand argon gases.

Q 34.

How does ammonia react with a solution of Cu2+?

Q 35.

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

Q 36.

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 37.

Give the formula and describe the structure of a noble gas species which is isostructural with:  (i) ICI4 (ii) IBr2 (iii) Br03

Q 38.

In a cyclotrimeta phosphoric acid molecule, how many single and double bonds are present? .
(a) 3 double bonds; 9 single bonds
(b) 6 double bonds; 6 single bonds
(c) 3 double bonds; 12 single bonds
(d) Zero double bonds; 12 single bonds

Q 39.

Which of the following pairs of ions are isoelectronic and isostructural?
ncert-exemplar-problems-class-12-chemistry-p-block-elements-6

Q 40.

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 41.

In the preparation of H2S06 by contact process, why is S03 not absorbed directly in water to form H2S04?

Q 42.

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

Q 43.

Explain why does the stability of oxoacids of chlorine increase in the order given below:
HClO < HClO2 < HClO3 < HClO4

Q 44.

P4O6 reacts with water according to equation P4O6 + 6H2O Calculate the volume of 0.1 M NaOH solution required to neutralize the acid formed by dissolving 1.1 g of P4O6 in H2O.

Q 45.

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 46.

An amorphous solid "A"bums in air to form a gas "B"which turns lime water milky. The gas is also produced as a by-product during roasting of sulphide ore. This gas decolourises acidified aqueous KMnO4  solution and reduces Fe3+ to Fe+2. Identify the solid "A"and the gas "B"and write the reactions involved.

Q 47.

 Why are pentahalides more covalent than trihalidcs?

Q 48.

 Why is N2 less reactive at room temperature?

Q 49.

Mention the conditions required to maximise the yield of ammonia.

Q 50.

 What is the covalence of nitrogen in N2O5 ?