wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

From the following data at 25C.

ReactionΔrH kJ/mol
12H2(g)+12O2(g)
+42
H2(g)+12O2(g)H2O(g)242
H2(g)2H(g)
O2(g)2O(g)
+436
+495

A
ΔrH for the reaction H2O(g)2H(g)+O(g) is 925.5 kJ/mol
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
ΔrH for the reaction OH(g)H(g)+O(g) is 502 kJ/mol
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
Enthalpy of formation of H(g) is 218 kJ/mol
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
Enthalpy of formation of H(g) is +218 kJ/mol
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct options are
A ΔrH for the reaction H2O(g)2H(g)+O(g) is 925.5 kJ/mol
D Enthalpy of formation of H(g) is +218 kJ/mol
A. H2O2H+O ΔH0r=242kJ/mol ......(1)
H22H ΔH0r=436kJ/mol ......(2)
12O ΔH0r=4952=247.5kJ/mol ......(3)
Add reactions (1) to (3)
H2O=2H+O
ΔH0r=242+436+247.5=925.5kJ/mol
Thus, the option A is correct.
H2(g)2H(g)ΔH0r=436kJ/mol......(1)
The expression for the enthalpy of formation of H(g) is
12H2(g)H(g)
It is obtained by dividing equation (1) with 2.
Enthalpy of formation of H(g) is 4362=218kJ/mol
Thus, the option D is correct.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Enthalpy
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon