NATIONAL OPEN UNIVERSITY OF NIGERIA
UNIVERSITY VILLAGE, PLOT 91 CADASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI – ABUJA.
FACULTY OF SCIENCES
DEPARTMENT OF PURE AND APPLIED SCIENCES
FEBRUARY/MARCH 2018 EXAMINATION
COURSE CODE: CHM 303
COURSE TITLE: INORGANIC CHEMISTRY III
TIME: 2⅟2 HOURS
INSTRUCTION: Question one is compulsory. Answer question one and
any other four questions.
QUESTION ONE
1ai) Discuss briefly why Group 1A elements are electropositive, and the trend of electropositivity among members of the group.41/2 marks
1aii) Complete this reaction:
XeF4 + Pt?2 marks
1aiii) Apart from oxygen other members of Group VI elements can make up to six covalent bonds, discuss.(2 marks)
1b) Comment on colour of transition metal compounds.91/2 marks
1ci) Depending on chemical composition, classify minerals of metals. (21/2 marks)
1cii) What are coordination compounds?(11/2 marks)
1ciii) Mention and explain the classes of coordination compounds.(3 marks)
.
QUESTION TWO
2ai) Discuss briefly the following:
i. The compound boron nitride
ii. Froth flotation process
iii. Rare earth elements 15 marks
QUESTION THREE
3ai) Discuss the periodic trend in atomic radii among transition elements. (4 marks
3aii) Distinguish between main group, transition and inner transition elements. (5marks)
3bi) Show with balanced chemical reaction the product formed when any nitrate of Group1A elements are heated. (2 marks)
3bii)Complete the following chemical equations. (4 marks)
i. 2K(s) + O2(g )
ii. 2Na(s) + 2H2O
QUESTION FOUR
Write short note on the following methods of metal purification:
I. Electrolysis
II. Zone refining
15 marks
QUESTION FIVE
5ai) Write on the following:
i. Four reasons why beryllium is different from other members of group IIA. (6 marks)
ii. Why caesium is a more reducing agent than sodium. (2marks)
5b) Describe formation of coordination compounds by Valence Bond Theory.(7 marks)
QUESTION SIX
6a) Write balanced chemical equations to show how reduction of iron oxide takes place in a blast furnace. (6 marks)
6b) List and explain briefly the steps involved in processing of metals from their ores after extraction/mining. (9 marks)
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Exam summary sample below
