Class 12 Chemistry - Chapter The p-Block Elements NCERT Solutions | What happens when H3PO3 is heated?

Why is helium used in diving apparatus?

Why are pentahalides more covalent than trihalides?

Give the formula and describe the structure of a noble gas species which is isostructural with:

(i) ICl^-₄

(ii) IBr^-₂

(iii) BrO^-₃

Why is H₂O a liquid and H₂S a gas?

How is O₃ estimated quantitatively?

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

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

Why are halogens strong oxidising agents?

Arrange the following in the order of property indicated for each set:

(i) F₂, Cl₂, Br₂, I₂- increasing bond dissociation enthalpy.

(ii) HF, HCl, HBr, HI - increasing acid strength.

(iii) NH₃, PH₃, AsH₃, SbH₃, BiH₃- increasing base strength.

Comment on the nature of two S-O bonds formed in SO₂ molecule. Are the two S-O bonds in this molecule equal?

For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt (III) chloride

(ii) Potassium tetracyanonickelate(II)

(iii) Tris(ethane-1,2-diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanoferrate(II)

(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N

(ii) Write IUPAC names of all the isomers.

(iii) What type of isomerism is exhibited by different pairs of amines?

Why are solids rigid?

Write any two characteristics of Chemisorption.

Write the structures of the following compounds.

(i) α-Methoxypropionaldehyde

(ii) 3-Hydroxybutanal

(iii) 2-Hydroxycyclopentane carbaldehyde

(iv) 4-Oxopentanal

(v) Di-sec-butyl ketone

(vi) 4-Fluoroacetophenone

Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?

Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?

Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.

Write structures of the following compounds:

(i) 2-Chloro-3-methylpentane

(ii) 1-Chloro-4-ethylcyclohexane

(iii) 4-tert. Butyl-3-iodoheptane

(iv) 1,4-Dibromobut-2-ene

(v) 1-Bromo-4-sec. butyl-2-methylbenzene

Give the IUPAC names of the following compounds:

(i) CH₃CH(Cl)CH(Br)CH₃

(ii) CHF₂CBrClF

(iii) ClCH₂C≡CCH₂Br

(iv) (CCl₃)₃CCl

(v) CH₃C(p-ClC₆H₄)₂CH(Br)CH₃

(vi) (CH₃)₃CCH=CClC₆H₄I-p

Ferric oxide crystallises in a hexagonal close-packed array of oxide ions with two out of every three octahedral holes occupied by ferric ions. Derive the formula of the ferric oxide.

Write the name and structure of one of the common initiators used in free radical addition polymerisation.

Explain the cleansing action of soaps.

Can you use soaps and synthetic detergents to check the hardness of water?

Write the mechanism of the reaction of HI with methoxymethane.

What happens when

(i) n-butyl chloride is treated with alcoholic KOH,

(ii) bromobenzene is treated with Mg in the presence of dry ether,

(iii) chlorobenzene is subjected to hydrolysis,

(iv) ethyl chloride is treated with aqueous KOH,

(v) methyl bromide is treated with sodium in the presence of dry ether,

(vi) methyl chloride is treated with KCN.

Write the names and structures of the monomers of the following polymers:

(i) Buna-S  (ii) Buna-N

(iii) Dacron  (iv) Neoprene

Name the reagents used in the following reactions:

(i) Oxidation of a primary alcohol to carboxylic acid.

(ii) Oxidation of a primary alcohol to aldehyde.

(iii) Bromination of phenol to 2,4,6-tribromophenol.

(iv) Benzyl alcohol to benzoic acid.

(v) Dehydration of propan-2-ol to propene.

(vi) Butan-2-one to butan-2-ol.

Explain the following terms with suitable examples:

(i) Schottky defect

(ii) Frenkel defect

(iii) Interstitials and

(iv) F-centres