Enthalpy change for the reaction,
4H (g) → 2H2 (g) is - 869.6 kJ
The dissociation energy of H - H bond is
-869.6 kJ
+434.8 kJ
+217.4 kJ
+217.4 kJ
B.
+434.8 kJ
4H (g) → 2H2 (g); ΔH = - 869.6 kJ
2H2 (g) → 4 H (g); ΔH = 869.6 kJ
H2 (g) → 2 H (g); ΔH = 869.6/2 = 434.8 kJ
A buffer solution is prepared in which the concentration of NH3 is 0.30 M and the concentration of NH4 is 0.20 M. If the equilibrium constant, Kb for NH3 equals 1.8 x 10-5, what is the pH of this solution?
log ( 2.7 = 0.43)
9.43
11.72
8.73
8.73
A.
9.43
The Correct order of increasing bond length of C - H, C-O, C - C and C = C is
C - C < C=C < C - O < C - H
C - O < C - H < C - C < C = C
C - H < C - O < C - C < C= C
C - H < C - O < C - C < C= C
D.
C - H < C - O < C - C < C= C
C - H: 0.109 nm
C = C : 0.134 nm
C - O: 0.143 nm
C - C : 0.154 nm
Therefore, Bond length order is
C - H < C = C < C- O < C - C
If the enthalpy change for the transition of liquid water to steam is 30kJ mol-1 at 27oC, the entropy change for the process would be.
1.0 J mol- K-1
0.1 J mol-1 K-1
100 J mol-1 K-1
100 J mol-1 K-1
C.
100 J mol-1 K-1
Which of the two ions from the list given below have the geometry that is explained by the same hybridization of orbitals,
D.
Hybridization of the given molecule is
therefore, both have the same hybridization.
Two gases A and B having the same volume diffuse through a porous partition in 20 and 10 seconds respectively. The molecular mass of A is 49u. Molecular mass of B will be
12.25 u
6.50 u
25.00 u
25.00 u
A.
12.25 u
Which of the following is the correct option for free expansion of an ideal gas under an adiabatic condition?
B.
For an adiabatic process, q = 0 and for free expansion, W = 0,
Therefore ΔT = 0.
A gaseous mixture was prepared by taking equal moles of CO and N2, If the total pressure of the mixture was found 1 atmosphere, the partial pressure of the nitrogen (N2) in the mixture is
0.8 atm
0.9 atm
1 atm
1 atm
C.
1 atm
If x is the amount of adsorbate and m is the amount of adsorbent, which of the following relations is not related to adsorption process?
p = f(T) at constant (x/m)
C.
The correct relation is
Which of the following is least likely to behave as Lewis base?
NH3
BF3
OH-
OH-
B.
BF3
BF3 is an electron deficient species, thus behaves like a Lewis acid.