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MT-30 CHEMISTRY
ANSWER KEY
1. (c) 2. (a) 3. (a) 4. (d) 5. (b) 6. (d) 7. (c) 8. (d) 9. (b) 10. (a)
11. (c) 12. (a) 13. (b) 14. (d) 15. (b) 16. (b) 17. (b) 18. (a) 19. (c) 20. (b)
21. (b) 22. (b) 23. (b) 24. (a) 25. (a) 26. (c) 27. (c) 28. (d) 29. (a) 30. (a)
HINTS & SOLUTIONS
1. (c) The configuration of atom of 4th period with maximum
unpaired electrons is 1s2 2s2 2p6 3s2 3p6 3d5 4s1.
Hence its atomic number is 24.
2. (a) The total numberof electrons in the molecular species
given, respectively are 17, 16 and 18. Write down the
electronic configuration of the molecular species and
observe the number of electrons in antibonding
orbitals which are respectively are 7, 6 and 8.
3. (a) Aluminium has greater affinity for oxygen and the
reaction is highly exothermic.
4. (d) Among alkaline earth metals, barium and radium have
the tendency to form peroxides.
5. (b) The more the reduction potential, the more is the
deposition of metals at cathode. Cation having E° value
less than – 0.83 V (reduction potential of H2O) will not
deposit from aqueous solution.
6. (d) There is very little difference in acid strength in the
series H3PO4, H3PO3 and H3PO2 because the
hydrogen in these acids are not all bonded to
phosphorus.
In the above three acids although the number of –OH
groups (ionisable hydrogen increases, yet the acidity
does not increase very much. This is due to the fact
that the number of unprotonated oxygen, responsible
for the enhancement of acidity due to inductive effect,
remains the same with the result dissociation constant
also remains nearly same.
7. (c) C(graphite) is the stable state of aggregation of
carbon.
8. (d) Reaction between diborane and alkene are carried out
in dry ether under an atmosphere of N2 because B2H6
and the products are very reactive. The products
further treated with alkaline H2O2 to convert into
alcohols.
2 2
alkaline
2 6 2 4 2 4 3 H O
reactive
B H 6C H B(C H )
3 2 3 33CH CH OH H BO
9. (b) Liquid crystals on heating first become turbid and
then clear.
10. (a) AgX + 2 Na2 S2O3 Na3 [Ag(S2O3)2]+ NaX
 Sodium argento thiosuphate
 (soluble complex)
11. (c) By definition, a mixed complex contains more than
one type of ligands.
12. (a) Osmotic pressure, = CRT ;
5.74
45.7n,
60
6n KClCOOHCH3
Since KCl ionises. Therefore its effective conc., in
solution increases.
13. (b)
14. (d) In reaction (d) oxidation number changes from + 4 in
NO2 to + 3 in HNO2 and + sin HNO3
15. (b) In neutral and alkaline medium
4 2 2MnO 2H O 3e MnO 4OH
In acidic medium:
2
4 2MnO 8H 5e Mn 4H O
16. (b) Ca
C
C
, 6.4g of CaC2 contain -electron = 4NA
17. (b)
C CH
+ CH – CH MgBr3 2
C H62
C CMg Br
+
18. (a) Because of the formation of the most stable
carbonium ion, 6 5 2C H CH
19. (c) Let atomic masses of A and B be a and b amu
respectively
 Molar mass of AB2 = (a + 2b) g mol–1
and Molar mass of AB4 = (a + 4b) g mol–1
For compound AB2
Tb = Kb WB 1000/ WA MB
2.3 = 5.1 1 1000/ 20.0 (a + 2b)....I
For compound AB4
1.3 = 5.1 1 1000/ 20.0 (a + 4b)....II
Solving (I) and (II), a = 25.49 b = 42.64
MOCK TEST 5 MT-31
20. (b) 2NaI + 2 2NaNO + 4 COOHCH3 2I + 2NO +
4 COONaCH3 + 2 OH2
The colour of CCl4 layer turns purple due to liberated
I2.
21. (b) For bcc lattice, number of atoms per unit cell = 2
Now 3 8 3 23
o
n M 2 100d
a N (4 10 cm) 6.02 10
= 200/38.528 = 5.19 g/cc
22. (b) Entiomers of C4H10O are
|
| |
3 2 3 3 2 3
|
H
OH HO
H CH C C CH H C C CH CH
H
4SO2H
A
3
|
23 CHH
OH
CCHCH
)C(Minor
322
)B(Major
33 CHCHCHCHCHCHCHCH
23. (b) In general 1/ 2t of reaction 
n 1
0
1
(a )
For a second order reaction,
1/ 2 n 1 00
1 1 1
t 10min
K(a ) 0.5 0.2K(a )
24. (a) 3 HCHO 
On keeping
aq. solution
CH2
CH2
O
O
CH2
O
Trioxane 
(meta formaldehyde)
25. (a)
base
saltlogpKpOH b
 41014pH;101log10log 10
26. (c)
C50
HCl,NaNO2
2NH
ClN2
2NMe
H
+
2NMeN = N
27. (c) The secondary amines react with HNO2 to give the
oily nitroso derivative. Amongst the options, (c) is
the secondary amine.
28. (d) The strongest oxidising agent is one which has
maximum tendency to gain electrons, i.e. whose E°Red
is maximum
29. (a) Phospholipids - Phosphate + glycerol + fatty acids +
a nitrogen containing base.
 General formula : 
XO
O
OH
POCH
|
''CORCHO
|
'COR.OCH
||
|
2
2
X = 
neEthanolami
222 NHCHOHCH ,
30. (a) Alkyl or Aryl cyanide react with grignard reagent to
form ketones
C N
+C H MgBr56
Ether
C H – C=NMgBr56
H O3
+
C
O
C H6 5
or 2
56
|
56 MgBrNHO
HC
CHC