Chemistry

The p-Block Elements.

Question:

Write the reactions of F2 and Cl2 with water.

Answer:


NCERT Solutions For Class 12 Chemistry Chapter 7 The p Block Elements Exercises Q28

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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.

Why does nitrogen show catenation properties less than phosphorus?

Q 5.

SF6 is known but SCl6 is not. Why?

Q 6.

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 7.

Why is ICI more reactive than l2?

Q 8.

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

Q 9.

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

Q 10.

How is the presence of SO2 detected ?

Q 11.

Why does NH3 form hydrogen bond but PH3 does not?

Q 12.

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

Q 13.

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 14.

Why is H2O a liquid and H2S a gas?

Q 15.

Give two examples to show the anomalous behaviour of fluorine.

Q 16.

Give the resonating structures of N02 and N2O5.

Q 17.

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 18.

 Why are halogens strong oxidising agents?

Q 19.

 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 20.

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

Q 21.

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

Q 22.

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

Q 23.

Explain why fluorine forms only one oxoacid, HOF.

Q 24.

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 25.

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 26.

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

Q 27.

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

Q 28.

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 29.

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

Q 30.

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 31.

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 32.

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 33.

How is ammonia manufactured industrially?

Q 34.

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

Q 35.

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

Q 36.

Why are halogens coloured?

Q 37.

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

Q 38.

How are xenon fluorides XeF2, XeF4 and XeFobtained?

Q 39.

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

Q 40.

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

Q 41.

Why is N2 less reactive at room temperature?

Q 42.

Bond angle in PH4+ is higher than that in PH3. Why?

Q 43.

How is O3 estimated quantitatively?

Q 44.

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 45.

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

Q 46.

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

Q 47.

Knowing the electron gain enthalpy values of O—>O and O—>O2- as -141 and 702 kJ mol-1 respectively, how can you account for [he formation of a large number of oxides having O2- species and not O?

Q 48.

Write the reactions of F2 and Cl2 with water.

Q 49.

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

Q 50.

List the uses of neoirand argon gases.