Chemistry NCERT Exemplar Solutions Class 12th Chapter Twelve: Overview, Questions, Preparation

An alkene ‘A’ (Mol. formula C⁵H¹⁰ on ozonolysis gives a mixture of two compounds ‘B’ and ‘C’. Compound ‘B’ gives positive Fehling’s test and forms an iodoform on treatment with I₂ and NaOH. Compound ‘C’ does not give Fehling’s test but forms an iodoform. Identify the compounds A, B and C. Write the reaction for ozonolysis and formation of iodoform from B and C.

An aromatic compound ‘A’ (Molecular formula C₈H₈O]) gives a positive 2, 4-DNP test. It gives a yellow precipitate of compound ‘B’ on treatment with iodine and sodium hydroxide solution. Compound ‘A’ does not give Tollen’s or Fehling’s test. On drastic oxidation with potassium permanganate it forms a carboxylic acid ‘C’ (Molecular formula C₇H₆O₂), which is also formed along with the yellow compound in the above reaction. Identify A, B and C and write all the reactions involved.

Write down functional isomers of a carbonyl compound with molecular formula C₃H₆O. Which isomer will react faster with HCN and why? Explain the mechanism of the reaction also. Will the reaction lead to the completion with the conversion of whole reactant into product at reaction conditions? If a strong acid is added to the reaction mixture what will be the effect on concentration of the product and why?

The Crystal Field Stabilization Energy (CFSE) of $\left[{\mathrm{C}\mathrm{o}\mathrm{F}}_3{\left({\mathrm{H}}_2\mathrm{O}\right)}_3\right]\left({\mathrm{\Delta }}_0<\mathrm{P}\right)$  is :

$250\mathrm{m}\mathrm{L}$ of a waste solution obtained from the workshop of a goldsmith contains $0.1\mathrm{M}$ ${\mathrm{A}\mathrm{g}\mathrm{N}\mathrm{O}}_3$ and $0.1\mathrm{M}\mathrm{A}\mathrm{u}\mathrm{C}\mathrm{l}$ . The solution was electrolyzed at $2\mathrm{V}$ by passing a current of $1\mathrm{A}$ for 15 minutes. The metal/metals electrodeposited will be : $\left({\mathrm{E}}_{{\mathrm{A}\mathrm{g}}^{+}/\mathrm{A}\mathrm{g}}^{\mathrm{o}}=0.8\mathrm{V},{\mathrm{E}}_{{\mathrm{A}\mathrm{u}}^{+}/\mathrm{A}\mathrm{u}}^{\mathrm{o}}=1.69\mathrm{V}\right)$

Among statements (a) - (d), the correct ones are:

(a) Lime stone is decomposed to $\mathrm{C}\mathrm{a}\mathrm{O}$ during the extraction of iron from its oxides.

(b) In the extraction of silver, silver is extracted as an anionic complex.

(c) Nickel is purified by Mond's process.

(d) Zr and Ti are purified by Van Arkel method.

The decreasing order of reactivity of the following organic molecules towards ${\mathrm{A}\mathrm{g}\mathrm{N}\mathrm{O}}_3$ solution is:

Bonding in which of the following diatonic molecule(s) become(s) stronger, on the basis of MO Theory, by removal of an electron?

(A) NO

(B) N₂

(C) O₂

(D) C₂

(E) B₂

Choose the most appropriate answer from the options given below

Leaching of gold with dilute aqueous solution of NaCN in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold an another complex [B], [A] and [B], respectively are