Class 12 Chemistry - Chapter The p-Block Elements NCERT Solutions | What happens when sulphur dioxide is pas

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?

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?

Mention the conditions required to maximise the yield of ammonia.

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

How will you bring about the following conversions?

(i) Ethanol to but-1-yne

(ii) Ethane to bromoethene

(iii) Propene to 1-nitropropane

(iv) Toluene to benzyl alcohol

(v) Propene to propyne

(vi) Ethanol to ethyl fluoride

(vii) Bromomethane to propanone

(viii) But-1-ene to but-2-ene

(ix) 1-Chlorobutane to n-octane

(x) Benzene to biphenyl.

Q1 : Write down the electronic configuration of:

(i) Cr³⁺    (iii) Cu⁺    (v) Co²⁺    (vii) Mn²⁺ 

(ii) Pm³⁺  (iv) Ce⁴⁺  (vi) Lu²⁺   (viii) Th⁴⁺

Why are cimetidine and ranitidine better antacids than sodium hydrogencarbonate or magnesium or aluminium hydroxide ?

What is the role of graphite rod in the electrometallurgy of aluminium?

Why is the ester hydrolysis slow in the beginning and becomes faster after sometime?

For the reaction:

2A + B → A₂B

the rate = k[A][B]²with k= 2.0 x 10^-6mol^-2L²s^-1. Calculate the initial rate of the reaction when [A] = 0.1 mol L^-1, [B] = 0.2 mol L^-1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L^-1.

Write equations of the following reactions:

(i) Friedel-Crafts reaction-alkylation of anisole.

(ii) Nitration of anisole.

(iii) Bromination of anisole in ethanoic acid medium.

(iv) Friedel-Craft's acetylation of anisole.

Determine the amount of CaCl2 (i = 2.47) dissolved in 2.5 litre of water such that its osmotic pressure is 0.75 atm at 27°C.

What are the factors which influence the adsorption of a gas on a solid?

The cell in which the following reactions occurs:

has E^ø_cell = 0.236 V at 298 K.

Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.