Section A
Q1. Answer all of the following:
(a)
Balance the following redox reaction in an acidic medium by the ion-electron method:
Cr2O7^{2-} + Fe^{2+} longrightarrow Cr^{3+} + Fe^{3+}
(b) When a few Si atoms are replaced by P atoms in pure crystal of Si, what is the consequence in the physical property?
(c) The effective magnetic moment of [Ni(NH3)_6]^{2*} is sim 3.20 B.M. Is it higher or lower or equal to the mu_{ ext{spin-only}} value ? Provide an explanation.
(d)
Identify the organometallic compound which obeys the 18 electron rule.
(i) [(eta7 - C7H7)Mo(CO)_3]^+
(ii) [(eta5 - C5H5)Fe(CO)_2]I
(e) Why are nuclei having 'Magic Number' of nucleons exceptionally stable ?
(f) Draw the structure of dimethyl beryllium and explain the bonding.
(g) Nowadays CFC (Chlorofluorocarbon)-free refrigerators are promoted in the market. Why and what is the consequence upon release of CFCs to the atmosphere? [Write only relevant reactions]
(h) Compared to other actinides, why have the chemical properties of Th and U been extensively developed?
(i) Find the oxidation states of (i) Br in Br3O8, and (ii) C in C3O2.
(j) The radii of Mo(Z = 42) and W(Z = 74) are 140 and 141 pm, respectively, despite the latter having many more electrons. Provide an explanation.
