CBSE
A reaction occurs spontaneously if
TS < H and both H and S are +ve
TS > H and both H and S are +ve
TS = H and both H and S are +ve
TS > H and H is +ve and S is - ve
The entropy values (in JK-1mol-1) of H2 (g) = 130.6, Cl2 (g) = 223.0 and HCl (g) = 186. 7 at 298 K and 1 atm pressure. Then entropy change for the reaction :
H2 ( g)+ Cl2 (g) 2HCl (g) is:
+540.3
+727.3
-166.9
+19.8
The change in entropy for the fusion of 1 mole of ice is [mp of ice = 273 K, molar enthalpy of fusion for ice= 6.0 kJ mol-1]
11.73 JK-1 mol-1
18.84 JK-1 mol-1
21.97 JK-1 mol-1
24.47 JK-1 mol-1
Which of the following have highest electron affinity?
F
Cl
N
O
The absolute enthalpy of neutralisation of the reaction
MgO(s) + 2HCl(aq) MgCl2(aq) + H2O(l)
will be
less than - 57.33 kJ mol-1
- 57.33 kJ mol-1
greater than-- 57.33 kJ mol-1
57.33 kJ mol-1
Consider the respective enthalpy for the following reactions:
None of the above
C(dia) + O2 CO2; = - 395.4 kJ/ mol
C(gr) + O2 CO2; H = - 393.5 kJ/ mol
C(gr) C(dia); H = ?
-3.8
-1.9
+3.8
+1.9
The enthalpy of combustion at 25°C of H2, cyclohexane (C6H12) and cyclohexene (C6H10) are -241, -3920 and -3800 kJ/mol respectively. The heat of hydrogenation of cyclohexene is :
-121 kJ/mol
+121 kJ/mol
-242 kJ/mol
+242 kJ/mol
Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction?
Exothermic and decreasing disorder
Endothermic and increasing disorder
Exothermic and increasing disorder
Endothermic and decreasing disorder
The entropy will be positive in which of the following reaction change.
H2(g) + I2 (g) 2HI (g)
HCl(g) + NH3 (g) N2O(g) + 2H2O(g)
NH4NO3(s)N2O(g) + 2H2O(g)
MgO(s) + H2(g) Mg(s) + H2O(l)