Of physisorption or chemisorption, which has a higher enthalpy of adsorption? 

Name the method used for refining of copper metal.

(a) Why does the presence of an excess of lithium make LiCl crystals pink?

(b) A solid with cubic crystal is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-center. What is the formula of the compound? 

How are interhalogen compounds formed? What general compositions can be assigned to them?

Draw the structures of the following molecules:

(i) XeF₆

(ii) H₂S₂O₇

Aluminum crystallizes in an fcc structure. Atomic radius of the metal is 125 pm. What is the length of the side of the unit cell of the metal? 

The standard electrode potential (E°) for Daniell cell is +1·1 V. Calculate the   G° for the reaction

Zn(s) + Cu²⁺ (aq)  ----> Zn⁺ (aq) + Cu (s)

(1 F = 96500 C mol^-1).

(a) For a reaction A + B -->  P, the rate law is given by,

r = k [A]^1/2 [B]².

What is the order of this reaction?

(b) A first order reaction is found to have a rate constant k = 5·5 x 10^-14 s^-1. Find the half-life of the reaction. 

Outline the principles of refining of metals by the following methods: 

(i) Zone refining

(ii) Vapour phase refining

Define the following terms giving an example of each:

(i) Associated colloids

(ii) Lyophilic sol

(iii) Adsorption