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-49
ncert-exemplar-problems-class-12-chemistry-p-block-elements-50

Answer:

(a) (A -> 4), (B - » 3), (C -> 1), (D - » 2)
(a) H2SO4 is used in storage batteries
(b) CCl3NO2 is known as tear gas.
(c) Cl2 has highest electron gain enthalpy.
(d) Sulphur is a member of chalcogen i.e., one producing elements.

previuos
next

The p-Block Elements.

Q 1.

How is O3 estimated quantitatively?

Q 2.

Name three oxoacids of nitrogen. Write the disproportionation reaction of that oxoacid of nitrogen in which nitrogen is in +3 oxidation state.

Q 3.

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

Q 4.

Discuss the trends in chemical reactivity of group 15 elements.

Q 5.

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

Q 6.

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

Q 7.

Why does nitrogen show catenation properties less than phosphorus?

Q 8.

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 9.

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

Q 10.

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

Q 11.

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

Q 12.

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 13.

Explain why fluorine forms only one oxoacid, HOF.

Q 14.

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

Q 15.

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.

Q 16.

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 17.

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

Q 18.

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

Q 19.

Give two examples to show the anomalous behaviour of fluorine.

Q 20.

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

Q 21.

 How are XeOand XeOF4prepared?

Q 22.

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

Q 23.

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

Q 24.

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

Q 25.

Write main differences between the properties of white phosphorus and red phosphorus.

Q 26.

Explain why fluorine forms only one oxoacid, HOF.

Q 27.

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 28.

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

Q 29.

Phosphorus forms a number of oxoacids. Out of these oxoacids phosphinic acid has strong reducing property. Write its structure and also write a reaction showing its reducing behaviour.

Q 30.

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 31.

 Why is N2 less reactive at room temperature?

Q 32.

 What is the covalence of nitrogen in N2O5 ?

Q 33.

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

Q 34.

What is the basicity of H3PO4?

Q 35.

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

Q 36.

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

Q 37.

Why is dioxygen a gas but sulphur a solid?

Q 38.

 Why do noble gases have comparatively large atomic size?

Q 39.

 List the uses of neoirand argon gases.

Q 40.

Why is N2 less reactive at room temperature?

Q 41.

What is the covalence of nitrogen in N2O5 ?

Q 42.

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

Q 43.

How is O3 estimated quantitatively?

Q 44.

Why does the reactivity of nitrogen differ from phosphorus?

Q 45.

Why does R3P = O exist but R3N = O does not (R = alkyl group)?

Q 46.

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

Q 47.

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

Q 48.

Why is dioxygen a gas but sulphur a solid?

Q 49.

How are xenon fluorides XeF2, XeF4 and XeF6  obtained?

Q 50.

How are XeO3  and XeOF4prepared?