Assign reasons for the following:
(i) Copper (I) ion is not known in aqueous solution.
(ii) Actinoids exhibit greater range of oxidation states than Lanthanoids.
Silver crystallizes in face-center cubic unit cell. Each side of this unit cell has a length of 400 pm. Calculate the radius of the silver atom. (Assume the atoms just touch each other on the diagonal across the face of the unit cell. That is each face atom is touching the four corner atoms.)
Nitrogen pentoxide decomposes according to equation: 2N2O5(g)---> 4NO2(g) + O2(g)
This first order reaction was allowed to proceed at 40° C and the data below were collected:
[N2O5] (M) |
Time (min) |
0.400 |
0.00 |
0.289 |
20.0 |
0.209 |
40.0 |
0.151 |
60.0 |
0.109 |
80.0 |
(a) Calculate the rate constant. Include units with your answer.
(b) What will be the concentration of N2O5 after 100 minutes?
(c) Calculate the initial rate of reaction.
Explain how the phenomenon of adsorption finds application in each of the following processes:
(i) Production of vacuum
(ii) Heterogeneous catalysis
(iii)Froth Floatation process
Define each of the following terms:
(i) Micelles
(ii)Peptization
(iii)Desorption
(i) A micelle is an aggregate of surfactant molecules dispersed in a liquid. A micelle in aqueous solution forms an aggregate such that the hydrophilic "head" regions are in contact with the surrounding solvent and the hydrophobic tail regions are in the center of micelle.
(ii) Peptization is the process of conversion of a precipitate into a colloidal sol by shaking it with the dispersion medium in the presence of an electrolyte. The electrolyte used in this reaction is known as a peptizing agent.
(iii) Desorption is the process of removing an adsorbed substance from the surface through which it was adsorbed.
Describe the principle behind each of the following processes:
(i)Vapour phase refining of a metal.
(ii)Electrolytic refining of a metal.
(iii)Recovery of silver after silver ore was leached with NaCN.
Write the name, stereochemistry and magnetic behavior of the following:
(At. nos. Mn = 25, Co = 27, Ni = 28)
(i) K4[Mn (CN)6]
(ii) [Co (NH3)5Cl]Cl2
(iii) K2[Ni (CN)4]