Chemistry

The p-Block Elements.

Question:

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

Answer:

(b) (A —> 4), (B->1), (C-> 2), (D ->3)
ncert-exemplar-problems-class-12-chemistry-p-block-elements-48

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The p-Block Elements.

Q 1.

Why does NH3 form hydrogen bond but PH3 does not?

Q 2.

In the ring test of NO3 ion.Fe2+ion reduces nitrate ion to nitric oxide, which combines with Fe2+  (aq.) ion to form brown complex. Write the reactions involved in the formation of brown ring.

Q 3.

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 4.

How does ammonia react with a solution of Cu2+?

Q 5.

What is the basicity of H3PO4?

Q 6.

How is ammonia manufactured industrially?

Q 7.

 Write two uses of ClO2

Q 8.

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

Q 9.

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

Q 10.

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

Q 11.

Nitric acid forms an oxide of nitrogen on reaction with P4O10. Write the reaction involved. Also write the resonating structures of the oxide of nitrogen formed.

Q 12.

 How is the presence of SO2 detected?

Q 13.

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

Q 14.

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

Q 15.

 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 16.

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

Q 17.

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

Q 18.

Give the resonating structures of N02 and N2O5.

Q 19.

Why does nitrogen show catenation properties less than phosphorus?

Q 20.

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 21.

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

Q 22.

List the uses of neoirand argon gases.

Q 23.

On heating with concentrated NaOH solution in an inert atmosphere of CO2, white phosphorus gives a gas. Which of the following statement is incorrect about the gas?
(a) It is highly poisonous and has smell like rotten fish.
(b) Its solution in water decomposes in the presence of light.
(c) It is more basic than NH3  
(d) It is less basic than NH3

Q 24.

Which of the following is correct for P4 molecule of white phosphorus?
(a) It has 6 lone pairs of electrons (b) It has six P – P single bonds
(c) It has three P – P single bonds (d) It has four lone pairs of electrons,

Q 25.

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 26.

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

Q 27.

SF6 is known but SCl6 is not. Why?

Q 28.

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

Q 29.

Mention the conditions required to maximise the yield of ammonia.

Q 30.

 What happens when PCl5 is heated?

Q 31.

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

Q 32.

Give the resonating structures of N02 and N2O5.

Q 33.

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

Q 34.

Explain why fluorine forms only one oxoacid, HOF.

Q 35.

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

Q 36.

What is the basicity of H3PO4?

Q 37.

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

Q 38.

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

Q 39.

How is the presence of SO2 detected ?

Q 40.

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 41.

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 42.

How are XeO3  and XeOF4prepared?

Q 43.

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 44.

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 45.

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 46.

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 47.

PH3 forms bubbles when passed slowly in water but NH3 dissolves. Explain.

Q 48.

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 49.

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

Q 50.

Why is H2O a liquid and H2S a gas?