21.

Write the equations involved in the following reactions:

(i) Reimer − Tiemann reaction
(ii) Williamson synthesis

Write the mechanism of the following reaction:

CH₃CH₂OH ---> HBrCH₃CH₂Br + H₂O

Write the names of monomers used for getting the following polymers:

(i) Bakelite
(ii) Neoprene

(a) Draw the structures of major monohalo products in each of the following reactions :


(b) Which halogen compound in each of the following pairs will react faster in SN2 reaction:
(i) CH₃Br or CH₃I
(ii) (CH₃)₃C−Cl or CH₃−Cl

Account for the following:
(i) Primary amines (R-NH₂) have higher boiling point than tertiary amines (R₃N).
(ii) Aniline does not undergo Friedel - Crafts reactions:
(iii) (CH₃)₂NH is more basic than (CH₃)₃N in an aqueous solution.

OR

Define the following terms as related to proteins:

(i) Peptide linkage
(ii) Primary structure
(iii) Denaturation

On the occasion of World Health Day, Dr Satpal organised a 'health camp' for the poor farmers living in a nearby village. After the check-up, he was shocked to see that most of the farmers suffered from cancer due to regular exposure to pesticides and many were diabetic. They distributed free medicines to them. Dr. Satpal immediately reported the matter to the National Human Rights Commission (NHRC). On the suggestions of NHRC, the government decided to provide medical care, financial assistance, setting up of super-speciality hospitals for treatment and prevention of the deadly disease in the affected villages all over India.
(i) Write the values shown by
(a) Dr. Satpal
(b) NHRC
(ii) What type of analgesics are chiefly used for the relief of pains of terminal cancer?
(iii) Give an example of artificial sweetener that could have been recommended to diabetic patients.

(a) Define the following terms :
(i) Molarity
(ii) Molal elevation constant (K_b)

(b) A solution containing 15 g urea (molar mass = 60 g mol^–1) per litre of the solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = 180 g mol^–1) in water. Calculate the mass of glucose present in one litre of its solution.

OR

(a) What type of deviation is shown by a mixture of ethanol and acetone? Give reason.

(b) A solution of glucose (molar mass = 180 g mol^–1) in water is labelled as 10% (by mass). What would be the molality and molarity of the solution?
(Density of solution = 1.2 g mL^–1)

(a) Complete the following equations :
(i) Cr₂O₇^2- + 2OH^- --->
(ii) MnO₄^- + 4H⁺ + 3e^- --->

(b) Account for the following :
(i) Zn is not considered as a transition element.
(ii) Transition metals form a large number of complexes.
(iii) The E° value for the Mn³⁺/Mn²⁺ couple is much more positive than that for Cr³⁺/Cr²⁺ couple.

OR

(i) With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids.

(ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
(iii) Complete the following equation :
MnO₄^- + 8H⁺ + 5e^---->
iv) Mn³⁺ is more paramagnetic than Cr³⁺.

(a) Write the products formed when CH3CHO reacts with the following reagents:
(i) HCN
(ii) H₂N−OH
(iii) CH₃CHO in the presence of dilute NaOH

(b) Give simple chemical tests to distinguish between the following pairs of compounds:
(i) Benzoic acid and Phenol
(ii) Propanal and Propanone

OR

(a) Account for the following:
(i) Cl−CH₂COOH is a stronger acid than CH₃COOH.
(ii) Carboxylic acids do not give reactions of the carbonyl group.

(b) Write the chemical equations to illustrate the following name reactions:
(i) Rosenmund reduction
(ii) Cannizzaro's reaction

(c) Out of CH₃CH₂−CO−CH₂−CH₃ and CH₃CH₂−CH₂−CO−CH₃, which gives iodoform test?