UNIVERSITY OF DAR ES SALAAM
CHEMISTRY DEPARTMENT
CH 219 TUTORIAL 4
1.
Explain why the stability of Group 15 (VA) hydrides follows the trend
NH3 > PH3 >AsH3 > SbH3 > BiH3.
2.
Write balanced chemical equations for the reaction of the following
compounds with water:
Al4C3
i.
ii.
CaC2
iii.
SbCl3
iv.
NCl3
3.
Explain the trend in acid strength for aqueous solutions of Group 16 (VIA)
H2M hydrides (excluding M = Oxygen).
4.
Aqueous solutions of ammonia are commonly referred to as ammonium
hydroxide. Discuss this statement illustrating your answer with relevant
balanced chemical equations.
5.
Explain why nitrogen does not exhibit hyper-coordination.
6.
Discuss and highlight the difference between the structure of graphite and
diamond.
7.
Write plausible reasons for each of the following:
(a) White phosphorus is more reactive than black phosphorus.
(b) At room temperature nitrogen exists as an N2 molecule whereas
phosphorus exists as a P4 molecule.
8.
Ammonia can be prepared by (a) the hydrolysis of Li 3 N or (b) the hightemperature, high-pressure reduction of N2 by H2. Give balanced chemical
equations for each method starting with N2, Li, and H2, as appropriate. (c)
Account for the lower cost of the second method.
9.
Carbon monoxide is a good ligand and is toxic. Why is the isoelectronic N 2
molecule not toxic?
10.
State whether the following oxides are acidic, basic, neutral, or amphoteric:
CO2, P2O5, SO3, MgO, K2O, Al2O3, CO.