Chemistry

The p-Block Elements.

Question:

Which of the following statements are correct?
(a) Among halogens, radius ratio between iodine and fluorine is maximum.
(b) Leaving F – F bond, all halogens have weaker X – X bond than X – X’ bond in interhalogens.
(c) Among interhalogen compounds maximum number of atoms ate present in iodine fluoride.
(d) Interhalogen compounds are more reactive than halogen compounds.

Answer:

(a, c, d) Among halogens radius ratio between iodine and fluorine is maximum because iodine has maximum radius while fluorine has minimum radius. Also, due to highest radius ratio maximum number of atoms are present in iodine fluoride.
Interhalogen compounds are more reactive than halogen compounds because A – B bond of dissimilar halogen is weaker than A – A or B – B bond of halogens.

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The p-Block Elements.

Q 1.

How does ammonia react with a solution of Cu2+?

Q 2.

Give the reason for bleaching action of Cl2.

Q 3.

Why are halogens strong oxidising agents?

Q 4.

 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 5.

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

Q 6.

Give the resonating structures of N02 and N2O5.

Q 7.

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 8.

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

Q 9.

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

Q 10.

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

Q 11.

Which of the following acid forms three series of salts?
(a) H2PO2  (b) H3BO3 (C)H3PO4(d)H3PO3

Q 12.

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

Q 13.

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

Q 14.

How is O3 estimated quantitatively?

Q 15.

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

Q 16.

Describe the manufacture of H2SO4 by contact process?

Q 17.

Write two uses of ClO2

Q 18.

Which of the following statements are correct?
(a) All three N – O bond lengths in HNO3 are equal.
(b) All P – Cl bond lengths in PCl5 molecule in gaseous state are equal.
(c) P4  molecule in white phosphorus have angular strain therefore white phosphorus is very reactive.
(d) PCl5 is ionic in solid state in which cation is tetrahedral and anion is octahedral.

Q 19.

Which of the following statements are true?
(a) Only type of interactions between particles of noble gases are due to weak dispersion forces.
(b) Ionisation enthalpy of.molecular oxygen is very close to that of xenon.
(c) Hydrolysis of XeF6 is a redox reaction.
(d) Xenon fluorides are not reactive.

Q 20.

Give two examples to show the anomalous behaviour of fluorine.

Q 21.

 Why does R3P=0 exist but R3N=0 does not (R is an alkyl group) ?

Q 22.

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

Q 23.

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

Q 24.

How is the presence of SO2 detected ?

Q 25.

In qualitative analysis when H2S is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. HNO3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives
ncert-exemplar-problems-class-12-chemistry-p-block-elements-3

Q 26.

If chlorine gas is passed through hot NaOH solution, two changes are observed in the oxidation number of chlorine during the reaction. These are —— and ——-

Q 27.

Which of the following options are not in accordance with the properly mentioned against them?
ncert-exemplar-problems-class-12-chemistry-p-block-elements-20

Q 28.

In which of the following reactions cone. H2S04 is used as an oxidizing reagent?
ncert-exemplar-problems-class-12-chemistry-p-block-elements-25

Q 29.

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

Q 30.

 What happens when PCl5 is heated?

Q 31.

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

Q 32.

Why has it been difficult to study the chemistry of radon?

Q 33.

 How is SO2 an air pollutant?

Q 34.

 Write two uses of ClO2

Q 35.

Why is N2 less reactive at room temperature?

Q 36.

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

Q 37.

Bond dissociation enthalpy of E – H (E = element) bonds is given below. Which of the compounds will act as strongest reducing agent?
ncert-exemplar-problems-class-12-chemistry-p-block-elements-7

Q 38.

 Why is N2 less reactive at room temperature?

Q 39.

Name two poisonous gases which can be prepared from chlorine gas

Q 40.

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

Q 41.

Give the resonating structures of N02 and N2O5.

Q 42.

Why is dioxygen a gas but sulphur a solid?

Q 43.

 Describe the manufacture of H2SO4 by contact process?

Q 44.

 With which neutral molecule is ClO isoelectronic? Is this molecule Lewis acid or base ? (Pb. Board 2009)

Q 45.

 List the uses of neoirand argon gases.

Q 46.

Why are pentahalides more covalent than trihalidcs ?

Q 47.

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

Q 48.

Why does NH3 form hydrogen bond but PH3 does not?

Q 49.

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

Q 50.

Why does nitrogen show catenation properties less than phosphorus?