NCERT Solutions Class 11 Chemistry Chapter 11 The P Block Elements Download In Pdf
Question 11.1 Discuss the pattern of variation in the oxidation states of (i) B to Tl and (ii) C to Pb.
Question 11.2 How can you explain higher stability of BCl3 as compared to TlCl3 ?
Question 11.3 Why does boron triflouride behave as a Lewis acid ?
Question 11.4 Consider the compounds, BCl3 and CCl4. How will they behave with water ? Justify.
Question 11.5 Is boric acid a protic acid ? Explain.
Question 11.6 Explain what happens when boric acid is heated .
Question 11.7 Describe the shapes of BF3 and BH4 –. Assign the hybridisation of boron in these species.
Question 11.8 Write reactions to justify amphoteric nature of aluminium.
Question 11.9 What are electron deficient compounds ? Are BCl3 and SiCl4 electron deficient species ? Explain.
Question 11.10 Write the resonance structures of CO3 2–and HCO3 – .
Question 11.11 What is the state of hybridisation of carbon in (a) CO3 2– (b) diamond (c) graphite?
Question 11.12 Explain the difference in properties of diamond and graphite on the basis of their structures.
Question 11.13 Rationalise the given statements and give chemical reactions : • Lead(II) chloride reacts with Cl2 to give PbCl4. • Lead(IV) chloride is highly unstable towards heat. • Lead is known not to form an iodide, PbI4.
Question 11.14 Suggest reasons why the B–F bond lengths in BF3 (130 pm) and BF4 – (143 pm) differ.
Question 11.15 If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.
Question 11.16 Aluminium trifluoride is insoluble in anhydrous HF but dissolves on addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous BF3 is bubbled through. Give reasons.
Question 11.17 Suggest a reason as to why CO is poisonous.
Question 11.18 How is excessive content of CO2 responsible for global warming ?
Question 11.19 Explain structures of diborane and boric acid.
Question 11.20 What happens when (a) Borax is heated strongly,
(b) Boric acid is added to water,
(c) Aluminium is treated with dilute NaOH,
(d) BF3 is reacted with ammonia ?
Question 11.21 Explain the following reactions
(a) Silicon is heated with methyl chloride at high temperature in the presence of copper;
(b) Silicon dioxide is treated with hydrogen fluoride;
(c) CO is heated with ZnO;
(d) Hydrated alumina is treated with aqueous NaOH solution.
Question 11.22 Give reasons :
(i) Conc. HNO3 can be transported in aluminium container.
(ii) A mixture of dilute NaOH and aluminium pieces is used to open drain.
(iii) Graphite is used as lubricant.
(iv) Diamond is used as an abrasive.
(v) Aluminium alloys are used to make aircraft body.
(vi) Aluminium utensils should not be kept in water overnight.
(vii) Aluminium wire is used to make transmission cables.
Question 11.23 Explain why is there a phenomenal decrease in ionization enthalpy from carbon to silicon ?
Question 11.24 How would you explain the lower atomic radius of Ga as compared to Al ?
Question 11.25 What are allotropes? Sketch the structure of two allotropes of carbon namely diamond and graphite. What is the impact of structure on physical properties of two allotropes?
Question 11.26 (a) Classify following oxides as neutral, acidic, basic or amphoteric: CO, B2O3, SiO2, CO2, Al2O3, PbO2, Tl2O3 (b) Write suitable chemical equations to show their nature.
Question 11.27 In some of the reactions thallium resembles aluminium, whereas in others it resembles with group I metals. Support this statement by giving some evidences.
Question 11.28 When metal X is treated with sodium hydroxide, a white precipitate (A) is obtained, which is soluble in excess of NaOH to give soluble complex (B). Compound (A) is soluble in dilute HCl to form compound (C). The compound (A) when heated strongly gives (D), which is used to extract metal. Identify (X), (A), (B), (C) and (D). Write suitable equations to support their identities.
Question 11.29 What do you understand by (a) inert pair effect (b) allotropy and (c) catenation?
Question 11.30 A certain salt X, gives the following results.
(i) Its aqueous solution is alkaline to litmus.
(ii) It swells up to a glassy material Y on strong heating.
(iii) When conc. H2SO4 is added to a hot solution of X,white crystal of an acid Z separates out. Write equations for all the above reactions and identify X, Y and Z.
Question 11.31 Write balanced equations for:
(i) BF3 + LiH →
(ii) B2H6 + H2O →
(iii) NaH + B2H6 →
(v) Al + NaOH →
(vi) B2H6 + NH3 →
Question 11.32. Give one method for industrial preparation and one for laboratory preparation of CO and CO2 each.
Question 11.33 An aqueous solution of borax is
Question 11.34 Boric acid is polymeric due to
(a) its acidic nature
(b) the presence of hydrogen bonds
(c) its monobasic nature
(d) its geometry
Question 11.35 The type of hybridisation of boron in diborane is
Question 11.36 Thermodynamically the most stable form of carbon i
s (a) diamond
Question 11.37 Elements of group 14
(a) exhibit oxidation state of +4 only
(b) exhibit oxidation state of +2 and +4
(c) form M2– and M4+ ion
(d) form M2+ and M4+ ions
Question 11.38 If the starting material for the manufacture of silicones is RSiCl3, write the structure of the product formed
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