An arco book arco is a registered trademark of Thomson Learning, Inc., and is used herein under license by Peterson’s. About The Thomson Corporation and Peterson’s

EXAMPLES:
Assertions (I)
Reasons (II)
Bubbling oxygen gas
BECAUSE
the solubility product
through a saturated solution
constant for this compound
of ZnCO
3
will cause the
is proportional to [O
2
]
3/2
.
sparingly soluble salt to
precipitate
The assertion in this question deals with a saturated solution of a sparingly soluble salt. The assertion
implies that ZnCO
3
dissolves into Zn
+2
, C
+4
, and 30
–2
; this implication is false. ZnCO
3 
dissolves to form
one Zn
+2
and one CO
3
–2
, so O
2
cannot function as a common ion in this situation. Likewise, the reason is
also false because the solubility product constant for this compound is K
sp
= [Zn
+2
] [CO
3
–2
].

---

Lesson 10
282
w w w . p e t e r s o n s . c o m / a r c o
ARCO
■ SAT II Subject Tests
The addition of 400mL of
BECAUSE
equal numbers of
2M H
2
SO
4
to 800mL of 1M
equivalents of a strong acid
NaOH will result in a
and a strong base react to
solution with neutral pH
form H
2
O and a neutral salt;
this reaction consumes the
added H
+
and OH
–
.
The question tests one’s ability to apply the concepts of concentration, normality, and titration (neutral-
ization). The number of equivalents of acid added must equal the number of equivalents of base present in
order to produce a solution with pH = 7, and the salt produced, in this case Na
2
SO
4
, must not contain ions
that are weak acids or weak bases. Two molar H
2
SO
4
is 4N with respect to [H
+
] while 1M KOH is 1N with
respect to [OH
–
]. Therefore, only 200mL of 2M H
2
SO
4
would be required to neutralize 800mL of 1M
NaOH. So the assertion is false, and the reason is true.
When a beam of alpha
BECAUSE
the alpha particles are