1 mole of H2SO4 is mixed with 2 moles of NaOH .The heat evolved will be :
57.3 kJ
2 x 57.3 kJ
57.3/2 kJ
Cannot be predicted
B.
2 x 57.3 kJ
1 mole of H2SO4 = 2g-equivalent of H2SO4 .Hence , when 1 mole of H2SO4 is mixed with 2 moles of NaOH , the heat evolved will be 2 x 57.3 kJ .
27Co60 is radioactive because :
its atomic number is high
it has high ratio
it has high ratio
None of the above
C.
it has high ratio
is radioactive and unstable due to high ratio .
Number of protons = 27
Number of neutrons = 33
for = = 1.22
One mole of which of the following has the highest entropy ?
Liquid nitrogen
Hydrogen gas
Mercury
Diamond
B.
Hydrogen gas
Entropy is the measure of degree of disorder (or randomness) of a system . The greater the disorder in a system , the higher is the entropy . Hence , entropy is highest for hydrogen gas .
Conjugate acid of CH3NH2 is :
CH3OH
CH3NH3+
CH2NH2+
CH3N-H
B.
CH3NH3+
Conjugate acid is obtained , when a base accepts a proton .
+
If the mass defect of is 0.090 u , then binding energy per nucleon is :
(1 u = 931.5 MeV)
9.315 MeV
931.5 MeV
83.0 MeV
8.38 MeV
A.
9.315 MeV
m = 0.090 u
Number of nucleons = 9
Binding energy per nucleon
=
=
= = 9.315 MeV
Amines behave as :
Lewis acid
Lewis base
aprotic acid
neutral compound
B.
Lewis base
The substance which. can donate a pair of electrons is called Lewis base .
Amines contain a lone pair of electrons on nitrogen atom which is available for donation , so they behave as Lewis base .
One mole. of a perfect gas expands isothermally to ten times of its original volume. The change in entropy is :
0.1 R
2.303 R
10.0 R
100.0 R
B.
2.303 R
S = 2.303nR log
n = 1
S = 2.303 R log
S = 2.303R (log 10 = 1)
100 cc of 0.6 N H2SO4 and 200 cc of 0.3 N HCl were mixed together .The normality of the solution will be :
0.2 N
0.4 N
0.8 N
0.6 N
B.
0.4 N
Normality of the mixed solution
=
=
=
=
= = 0.4 N
For the reaction :
N2 + 3H2 2NH3 ; H = ?
E + 2RT
E - 2RT
E + RT
E - RT
B.
E - 2RT
N2 + 3H2 2NH3
H = E + ngRT
ng = np - nr = 2 - 4 = -2
H = E + (-2)RT
H = E - 2RT
50 mL of 0.1 M HCl and 50 mL of 0.2 M NaOH are mixed .The pH of the resulting solution is :
1.30
4.2
12.70
11.70
C.
12.70
50 mL of0.1 M HCl = = 5 x 10-3
50 mL of 0.2 M NaOH = = 10 x 10-3
Hence , after neutralisation NaOH left
= 10 x 10-3 - 5 x 10-3 = 5 x 10-3
Total volume = 100 cc
The concentration of NaOH
= = 0.05 M
[OH-] = 0.05 M = 5 x 10-2 M
pOH = - log [OH-]
= - log [5 x 10-2]
= 1.3010
pH + pOH = 14
pH = 14 - 1.3010
= 12.699
= 12.70
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