Chemistry:2016:CBSE:[All India]:Set-II

The IUPAC name of the given compound is 2-phenylethanol.

 

The possible isomers from the formula C₄H₉Br are 1-Bromobutane, 2-Bromobutane, 1-Bromo2-methylpropane and 2-Bromo2-methylpropane. The isomer of C₄H₉Br, which is the most reactive towards S_N1 reaction is the one that forms a tertiary carbocation upon the elimination of the leaving group. This isomer is 2-Bromo2-methylpropane and its structure is shown below:

There are two main reasons for the stability of colloidal sols:

1. Electrostatic stabilisation: The stability of a colloidal solution is mainly due to the presence of equal and similar charges on the colloidal particles. The colloidal particles repel one another and are thus are unable to combine together to form larger particles. This keeps them dispersed in the medium and the colloidal solution remains stable. This is why sol particles do not settle down even on standing for a long time. 
 

2. Brownian movement: The constant rapid zig-zag motion of the particles plays an important role in imparting stability to the sol. This is because Brownian movement opposes the gravitational forces acting on colloidal particles and prevents them from settling down.

The examples of molecular solids include ice (H₂O) and solid ammonia.

The examples of ionic solids include sodium chloride (NaCl) and magnesium oxide (MgO).

Pb(NO₃)₂ on heating gives brown coloured nitrogen dioxide gas which on cooling dimerizes to dinitrogen tetroxide (N₂O₄).

 

(i) Since, rate = k, the given reaction is a zero-order reaction. On the basis of stoichiometry, the molecularity of the reaction is 2.

(ii) The unit of rate constant (k) is mole L^–1 sec^–1.

 

i. Hofmann bromamide degradation reaction:
It is the method of preparation of primary amines in which acid amide is treated with an aqueous or ethanolic solution of sodium hydroxide and bromine. Primary amine so formed has one carbon atom less than the original amide. The reaction is used in step down conversion.

ii. Carbylamine reaction
The reaction is used as a test for primary amines. Aliphatic and aromatic primary amines on heating with chloroform and alcoholic potassium hydroxide form isocyanides that are foul smelling substances.

i.  According to Henry’s law, the solubility of a gas is inversely related to the Henry’s constant (K_H) for that gas. Since, gas (B), is less soluble, it will have a higher K_H value.

ii. A maximum boiling azeotrope shows negative deviation from the Raoult’s law.

(i)   Formation of 3 moles of AgCl indicates that all the 3 Cl^– ions in the coordination compound CoCl₃.6NH₃ must be present outside the coordination sphere and they will satisfy the primary valency. Therefore, the structural formula of the complex will be [Co(NH₃)₆]Cl₃.

(ii) The IUPAC name of the complex is Hexaamminecobalt (III) chloride.

i. Structure of BrF₃: Bent T-shaped

ii. Structure of XeF₄: Square planar