CBSE (Commerce) Class 11CBSE
Account
It's free!

Share

Books Shortlist

# NCERT solutions Chemistry Class 11 Part 2 chapter 11 The p-Block Elements

## Chapter 11 - The p-Block Elements

#### Pages 323 - 325

Discuss the pattern of variation in the oxidation states of  B to Tl

Q 1.1 | Page 323

Discuss the pattern of variation in the oxidation states of C to Pb.

Q 1.2 | Page 323

How can you explain higher stability of BClas compared to TlCl3?

Q 2 | Page 323

Why does boron trifluoride behave as a Lewis acid?

Q 3 | Page 323

Consider the compounds, BCland CCl4. How will they behave with water? Justify.

Q 4 | Page 323

Is boric acid a protic acid? Explain.

Q 5 | Page 323

Explain what happens when boric acid is heated.

Q 6 | Page 323

Describe the shapes of BF3 and BH4. Assign the hybridisation of boron in these species.

Q 7 | Page 323

Write reactions to justify amphoteric nature of aluminium.

Q 8 | Page 323

What are electron deficient compounds? Are BCl3 and SiCl4 electron deficient species? Explain

Q 9 | Page 324

Write the resonance structure of  CO_3^(2-)

Q 10.1 | Page 324

Write the resonance structures of HCO_3^(-)

Q 10.2 | Page 324

What is the state of hybridisation of carbon in CO_3^(2-)

Q 11.1 | Page 324

What is the state of hybridisation of carbon in Diamond ?

Q 11.2 | Page 324

What is the state of hybridisation of carbon in graphite?

Q 11.3 | Page 324

Explain the difference in properties of diamond and graphite on the basis of their structures.

Q 12 | Page 324

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

Q 13 | Page 324

Suggest reasons why the B–F bond lengths in BF3 (130 pm) and BF_4^(-) (143 pm) differ.

Q 14 | Page 324

If B–Cl bond has a dipole moment, explain why BCl3 molecule has zero dipole moment.

Q 15 | Page 324

Aluminium trifluoride is insoluble in anhydrous HF but dissolves on the addition of NaF. Aluminium trifluoride precipitates out of the resulting solution when gaseous BF3 is bubbled through. Give reasons.

Q 16 | Page 324

Suggest a reason as to why CO is poisonous.

Q 17 | Page 324

How is an excessive content of COresponsible for global warming?

Q 18 | Page 324

Explain Structures of Diborane and Boric Acid.

Q 19 | Page 324

What happens when Borax is heated strongly

Q 20.1 | Page 324

What happens when Boric acid is added to water

Q 20.2 | Page 324

What happens when Aluminium is treated with dilute NaOH

Q 20.3 | Page 324

What happens when BF3 is reacted with ammonia?

Q 20.4 | Page 324

Explain the following reactions

Silicon is heated with methyl chloride at high temperature in the presence of copper

Q 21.1 | Page 324

Explain the following reactions

Silicon dioxide is treated with hydrogen fluoride;

Q 21.2 | Page 324

Explain the following reactions CO is heated with ZnO;

Q 21.3 | Page 324

Explain the following reactions

Hydrated alumina is treated with aqueous NaOH solution.

Q 21.4 | Page 324

Give reasons for Conc. HNO3 can be transported in aluminium container.

Q 22.1 | Page 324

Give reasons: A mixture of dilute NaOH and aluminium pieces is used to open drain.

Q 22.2 | Page 324

Give reasons: Graphite is used as a lubricant.

Q 22.3 | Page 324

Give reasons: Diamond is used as an abrasive.

Q 22.4 | Page 324

Give reasons: Aluminium alloys are used to make aircraft body.

Q 22.5 | Page 324

Give reasons: Aluminium utensils should not be kept in water overnight.

Q 22.6 | Page 324

Give reasons:  Aluminium wire is used to make transmission cables.

Q 22.7 | Page 324

Explain why is there a phenomenal decrease in ionisation enthalpy from carbon to silicon?

Q 23 | Page 324

How would you explain the lower atomic radius of Ga as compared to Al?

Q 24 | Page 324

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?

Q 25 | Page 324

Classify following oxides as neutral, acidic, basic or amphoteric:

CO, B2O3, SiO2, CO2, Al2O3, PbO2, Tl2O3

Write suitable chemical equations to show their nature.

Q 26 | Page 325

In some of the reactions thallium resembles aluminium, whereas in others it resembles with group I metals. Support this statement by giving some evidences.

Q 27 | Page 325

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 the metal. Identify (X), (A), (B), (C) and (D). Write suitable equations to support their identities.

Q 28 | Page 325

What do you understand by inert pair effect

Q 29.1 | Page 325

What do you understand by Allotropy?

Q 29.2 | Page 325

What do you understand by catenation?

Q 29.3 | Page 325

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 XY and Z.

Q 30 | Page 325

Write balanced equations for: BF3 + LiH →

Q 31.1 | Page 325

Write balanced equations for: B2H6 + H2O →

Q 31.2 | Page 325

Write balanced equations for:  NaH + B2H6 →

Q 31.3 | Page 325

Write balanced equations for:

Q 31.4 | Page 325

Write balanced equations for: Al + NaOH →

Q 31.5 | Page 325

Write balanced equations for: B2H6 + NH3 →

Q 31.6 | Page 325

Give one method for industrial preparation and one for laboratory preparation of CO and CO2 each.

Q 32 | Page 325

Boric acid is polymeric due to

(a) its acidic nature

(b) the presence of hydrogen bonds

(c) its monobasic nature

(d) its geometry

Q 34 | Page 325

The type of hybridisation of boron in diborane is

(a) sp

(b) sp2

(c) sp3

(d) dsp2

Q 35 | Page 325

Thermodynamically the most stable form of carbon is

(a) diamond

(b) graphite

(c) fullerenes

(d) coal

Q 36 | Page 325

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

Q 37 | Page 325

If the starting material for the manufacture of silicones is RSiCl3, write the structure of the product formed.

Q 38 | Page 325

S