1
IIT-JEE 2012 Paper 2 Offline
+3
-1

Using the data provided, calculate the multiple bond energy (kJ mol$$-$$1) of a C=C bond in C2H2. That energy is (take the bond energy of C-H bond as 350 kJ mol$$-$$1).

$$\matrix{ \hfill {2C(s) + {H_2}(g) \to {C_2}{H_2}} & \hfill {\Delta H = 225\,kJ\,mo{l^{ - 1}}} \cr \hfill {2C(s) \to 2C(g)} & \hfill {\Delta H = 1410\,kJ\,mo{l^{ - 1}}} \cr \hfill {{H_2}(g) \to 2H(g)} & \hfill {\Delta H = 330\,kJ\,mo{l^{ - 1}}} \cr }$$

A
1165 kJ mol$$-$$1
B
837 kJ mol$$-$$1
C
865 kJ mol$$-$$1
D
815 kJ mol$$-$$1
2
IIT-JEE 2011 Paper 2 Offline
+4
-1
Match the transformations in column I with appropriate options in column II

Column I
(A) CO2(s) $$\to$$ CO2(g)
(B) CaCO3(s) $$\to$$ CaO(s) + CO2(g)
(C) 2H $$\to$$ H2(g)
(D) P(white, solid) $$\to$$ P(red, solid)

Column II
(p) phase transition
(q) allotropic change
(r) $$\Delta H$$ is positive
(s) $$\Delta S$$ is positive
(t) $$\Delta S$$ is negative
A
A $$\to$$ p,r,s; B $$\to$$ r,s; C $$\to$$ t; D $$\to$$ p,q,t
B
A $$\to$$ r,s; B $$\to$$ p,s; C $$\to$$ t; D $$\to$$ p,q,t
C
A $$\to$$ p,r,s; B $$\to$$ r,s; C $$\to$$ r; D $$\to$$ p,t
D
A $$\to$$ p,r,s; B $$\to$$ r,s; C $$\to$$ t; D $$\to$$ q,t
3
IIT-JEE 2010 Paper 1 Offline
+3
-0.75
The species which by definition has ZERO standard molar enthalpy of formation at 298 K is
A
Br2 (g)
B
Cl2 (g)
C
H2O (g)
D
CH4 (g)
4
IIT-JEE 2010 Paper 1 Offline
+1
-0.25
The bond energy (in kcal mol-1) of a C-C single bond is approximately
A
1
B
10
C
100
D
1000
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