Class 12 Chemistry - Chapter General Principles and Processes of Isolation of Elements NCERT Solutions | Differentiate between "minerals&quo

What is the significance of leaching in the extraction of aluminium?

Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.

Copper can be extracted by hydrometallurgy but not zinc. Explain.

Outline the principles of refining of metals by the following methods:

(i) Zone refining

(ii) Electrolytic refining

(iii) Vapour phase refining

Name the common elements present in the anode mud in electrolytic refining of copper. Why are they so present ?

The reaction,

      Cr₂O₃  +  2Al    →    Al₂O₃  + 2Cr            (ΔG_o = -421kJ)

is thermodynamically feasible as is apparent from the Gibbs energy value. Why does it not take place at room temperature?

How can you separate alumina from silica in bauxite ore associated with silica? Give equations, if any.

Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

Write chemical reactions taking place in the extraction of zinc from zinc blende.

Describe a method for refining nickel.

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

Why are pentahalides more covalent than trihalides?

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

The oxidation number of cobalt in K[Co(CO)₄] is

(i) +1

(ii) +3

(iii) -1

(iv) -3

An organic compound (A) (molecular formula C₈H₁₆O₂) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) on dehydration gives but-1-ene.Write equations for the reactions involved.

What is meant by positive & negative deviations from raoult’s law & how is the sign of ΔmixH related to positive & negative deviations from Raoult’s law?

Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.

Why does the conductivity of a solution decrease with dilution?

Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.

Distinguish between

(i)Hexagonal and monoclinic unit cells

(ii) Face-centred and end-centred unit cells.

What are alloys? Name an important alloy which contains some of thelanthanoid metals. Mention its uses.

Draw the structures of the following compounds.

(i) 3-Methylbutanal                           (ii) p-Nitropropiophenone

(iii) p-Methylbenzaldehyde               (iv) 4-Methylpent-3-en-2-one

(v) 4-Chloropentan-2-one                 (vi) 3-Bromo-4-phenylpentanoic acid

(vii) p,p'-Dihydroxybenzophenone    (viii) Hex-2-en-4-ynoic acid

Which alkyl halide from the following pairs would you expect to react more rapidly by an S_N2 mechanism? Explain your answer.