|
Answers
1.
Ans: B
Acids
react with bases to form salt
and water. Alkalis liberate
ammonia from ammonium salts.
Although HCl is a strong acid,
it will not liberate hydrogen
when added to unreactive metals
such as Cu, Ag (silver) and
Au (gold). Finally acids turn
blue litmus paper red.
2.
Ans: A
Ammonia
is the only alkaline gas of
the group and so will turn red
litmus to blue.
3.
Ans: B
An
acid has a low pH value. Generally,
the smaller the pH value, the
stronger the concentration of
H+ ions in the solution. Thus,
a value of 1 would indicate
high concentration of H+ ions.
Alkalis on the other hand would
have pH values from 9-14.
4.
Ans: C
Magnesium
is the only metal of the group
and so when it burns in air
it forms a metallic oxide, MgO,
which is basic. This oxide dissolves
slightly in water to form a
slightly alkaline solution with
pH greater than seven.
5.
Ans: B
Zinc
carbonate reacts with suphuric
acid to form zinc sulphate,
carbon dioxide and water.
ZnCO3
(s) + H2SO4
(aq) === ZnSO4 (aq)
+ CO2 (g) + H2O
(l)
Only
a gas, H2 is produced
when zinc reacts with H2SO4.
Zn
(s) + H2SO4
(aq) === ZnSO4 (aq)
+ H2 (g)
The
other reactions do not produce
any gas, only the salt (ZnSO4)
and water.
|
