c) pH = pKb + log ([B] / [HB
+
])
d) pH = pK
a
+ log ([A
-
] / [HA])
e) pH = pK
a
+ 2log ([A
-
] / [HA])
Correct Answer:
d) pH = pK
a
+ log ([A
-
] / [HA])
Explanation:
The Henderson-Hasselbalch equation explains whether a compound will exist in its acidic form or in
its basic form at a particular pH. [A
-
] = Molar concentration of a conjugate base. [HA] = Molar
concentration of an undissociated weak acid (M).
Question 13
An azeotropic mixture is also called
a) Increased boiling mixture
b) Decreased boiling mixture
c) Constant boiling mixture
d) Either a or b
e) None of these
Correct Answer:
c) Constant boiling mixture
Explanation:
A pure chemical compound boils at a constant temperature and distils over completely at the same
temperature without any change in composition. It is also known as constant boiling mixture.
Question 14
A system is said to be in equilibrium at all the times. Such a process is called
a) Irreversible process
b) Equilibrium process
c) Static process
d) Quasi-static process
e) Reversible process
Correct Answer:
d) Quasi-static process
Explanation:
A quasi-static process is the one in which the system may be considered to be in equilibrium at all
times.
Question 15
Which one of the following is an intensive property?
a) Volume
b) Density
c) Mass
d) Energy
e) None of these.
Correct Answer:
b) Density