GENERAL QUESTIONS VI 219
GENERAL QUESTIONS VI
ELEMENTS OF GROUP III
- Make a table of all the elements of Group III, giving in
succeeding columns: (1) the symbols of the elements in the order
of their increasing atomic weights, placing the elements of the A
Family in the left of the column, and of the B Family in the right;
(2) the formula of the hydroxide, or hydroxides, if more than one
is described in reference books; (3) the character of the hydroxide,
distinguishing strongly acid, weakly acid, amphoteric, weakly
basic, and strongly basic; (4) the formula of the chloride, or chlor-
ides; (5) the degree of hydrolysis of the chloride, distinguishing
complete, much, little, or none.
- Compare aluminum hydroxide with the hydroxides of sodium
and magnesium, the corresponding elements in Groups I and II,
as regards solubility and degree of ionization.
- Compare the thermal stability of magnesium and aluminum
carbonates — of dry magnesium and aluminum sulphates. What
do the facts thus cited show as to the relative basic strength of
magnesium and aluminum oxides?
- Describe the successive observations that are made when
NaOH solution is added gradually to an A1C1 3 solution until an
excess of the base is present. Likewise describe observations
when HC1 solution is added gradually to an Na 3 A10 3 solution
until the acid is in excess. Write fully ionized intersecting equa-
tions corresponding to each observation, and explain how the
amphoteric character of aluminum hydroxide is manifested in this
experiment.
