Class 12 Chemistry - Chapter General Principles and Processes of Isolation of Elements NCERT Solutions | Is it true that under certain conditions

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

Using IUPAC norms write the systematic names of the following:

(i) [Co(NH₃)6]Cl₃

(ii) [Pt(NH₃)₂Cl(NH₂CH₃)]Cl

(iii) [Ti(H₂O)6]³⁺

(iv) [Co(NH₃)₄Cl(NO₂)]Cl

(v) [Mn(H₂O)6]²⁺

(vi) [NiCl₄]^2-

(vii) [Ni(NH₃)₆]Cl₂

(viii) [Co(en)₃]³⁺

(ix) [Ni(CO)₄]

Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.

In terms of band theory, what is the difference

(i) Between a conductor and an insulator

(ii) Between a conductor and a semiconductor

Give two reactions that show the acidic nature of phenol. Compare acidity of phenol with that of ethanol.

Which of the following lattices has the highest packing efficiency

(i) simple cubic

(ii) body-centred cubic and

(iii) hexagonal close-packed lattice?

Suggest a list of metals that are extracted electrolytically.

While antacids and anti allergic drugs interfere with the function of histamines, why do these not interfere with the function of each other ?

What happens when D-glucose is treated with the following reagents? (i)HI (ii)Bromine water (iii)HNO₃

Write the equation of the reaction of hydrogen iodide with:

(i) 1-propoxypropane

(ii) Methoxybenzene and

(iii) Benzyl ethyl ether

Write the chemical equation for preparing sodium soap from glyceryl oleate and glyceryl palmitate. Structural formulae of these compounds are given below.

(i) (C₁₅H₃₁COO)₃ C₃H₅ - Glyceryl palmitate

(ii)(C₁₇H₃₃COO)₃ C₃H₅ - Glyceryl oleate