What is the cause of a feeling of depression in human beings? Name a drug which can be useful in treating this depression.
Explain the following behaviours:
(i) Alcohols are more soluble in water than the hydrocarbons of comparable molecular masses.
(ii) Ortho-nitro phenol is more acidic than ortho-methoxyphenol.
Explain the mechanism of acid catalysed hydration of an alkene to form corresponding alcohol.
Complete the following chemical reaction equations:
(i) C6H5N2Cl + H3PO2+ H2O --->
(ii) C6H5NH2+ Br2(aq.)--->
Describe the following giving the relevant chemical equation in each case:
(i) Carbylamines reaction
(ii) Hofmann’s bromamide reaction.
Answer the following question:
(i) What is meant by the chirality of a compound? Give an example.
(ii) Which one of the following compounds is more easily hydrolyzed by KOH and why?
CH3CHCICH2CH3 or CH3CH2CH2Cl
(iii) Which one undergoes S N 2 substitution reaction faster and why?
(i)Chirality: It is a geometrical property of a rigid object ( or molecules ) by which it gets such spatial arrangement of points or atoms that, the molecule becomes non-super imposable of its mirror image.
The chiral molecule of the object does not have any element of symmetry like, a mirror image, centre of inversion (i) etc.
3-bromopent-1-ene is represented as
The centre of chirality is designated as *. It is due to the presence of four different groups.
(ii) Due to +I effect of alkyl groups the 2° carbonium ion CH3—CH+ —CH2—CH3 derived from sec. butyl chloride is more stable than the 1° carbonium ion CH3—CH2—C H2+ derived from n-propyl chloride. Therefore sec. butyl chloride gets hydrolyzed more easily than n-propyl chloride under SN1 conditions.
(iii) Undergoes SN2 substitution reaction faster.
Define the following as related to proteins:
(i) Peptide linkage
(ii) Primary structure
(iii) Denaturation
Differentiate between thermoplastic and thermosetting polymers. Give one example of each.
(a) Draw the molecular structure of the following compounds.
(i) N2O5
(ii) XeOF4
(b) Explain the following observation:
(i) Sulphur has a greater tendency for catenation than oxygen.
(ii) ICI is more reactive than I2.
(iii) Despite the lower value of its electron gain enthalpy with a negative sign, fluorine (F2) is a stronger oxidizing agent than Cl2.