Chemistry_Today_April_2017_vk_com_stopthepress

Reaction order Half-life (days)
(a) First 2
(b) First 6
(c) Second 2
(d) Zero 6
7. The number of possible enantiomeric pairs that
can be produced during mono-chlorination of
2-methylbutane is
(a) 3 (b) 4 (c) 1 (d) 2
8. The degree of dissociation (α) of a weak electrolyte,
A x B y is related to van't Hoff factor (i) by the
expression
x
(a) α= + y − 1
x
(b) α= + y + 1
i −1
i −1
i −1
i −1
(c) α=
(d) α=
( x+ y−1)
x+ y+
1
9. The coagulation values in millimoles per litre of
the electrolytes used for the coagulation of As 2 S 3 are
given below :
I. NaCl = 52
II. BaCl 2 = 0.69
III. MgSO 4 = 0.22
The c or r e order c t of their coagulating power is
(a) I > II > III (b) II > I > III
(c) III > II > I (d) III > I > II
10. In the following sequence of the reactions, identify
the final product D.
(a)
(c)
(d)
+
(b)
+
11. Pick out the incorrect statements from the
following.
1. Glucose exists in two different crystalline
forms, a-D-glucose and b-D-glucose.
2. a-D-glucose and b-D-glucose are anomers.
3. a-D-glucose and b-D-glucose are enantiomers.
4. Cellulose is a straight chain polysaccharide
made of only b-D-glucose units.
5. Starch is a mixture of amylose and
amylopectin, both contain unbranched chain
of a-D-glucose units.
(a) 1 and 2 only (b) 2 and 3 only
(c) 3 and 4 only (d) 3 and 5 only
12. When the imidazole ring of histidine is protonated,
the tendency of nitrogen to be protonated (proton
migrates from –COOH) is in the order
(a) b > g > a
(b) g > b > a
(c) g > a > b
(d) b > a > g
Assertion & Reason Type
Directions : In the following questions, a statement of assertion
is followed by a statement of reason. Mark the correct choice as :
(a) If both assertion and reason are true and reason is the
correct explanation of assertion.
(b) If both assertion and reason are true but reason is not the
correct explanation of assertion.
(c) If assertion is true but reason is false.
(d) If both assertion and reason are false.
13. Assertion : A mixture of 2-nitrophenol and
4-nitrophenol can be separated by steam
distillation.
Reason : 2-Nitrophenol is intramolecularly
H-bonded while 4-nitrophenol is intermolecularly
H-bonded.
14. Assertion : Chloroform is stored in dark coloured
bottles.
Reason : Chronic chloroform exposure may cause
damage to liver and kidneys.
15. Assertion : Hydrometallurgy involves dissolving the
ore in a suitable reagent followed by precipitation
by a more electropositive metal.
Reason : Copper in bulk quantity is extracted by
hydrometallurgy.
CHEMISTRY TODAY | APRIL ‘17 55