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Consider the following reaction : (A) ...

Consider the following reaction :
(A) `H^(+)(aq) + OH^(-)(aq) = H_(2)O(l): Delta H = -X_(1) kJ mol^(-1)`
(B) `H_(2)(g) + (1)/(2) O_(2)(g) = H_(2)O(l): Delta H = -X_(2) kJ mol^(-1)`
( C ) `CO_(2)(g) + H_(2)(g) = CO(g) + H_(2)O(l): Delta H = -X_(3) kJ mol^(-1)`
(D) `C_(2)H_(2)(g) + (5)/(2) O_(2)(g) = 2CO_(2) + H_(2)O(l): Delta H = +X_(4) kJ mol^(-1)`
Enthalpy of formation of `H_(2)O(l)` is :

A

`+ X_(1) kJ mol^(-1)`

B

`- X_(2) kJ mol^(-1)`

C

`+ X_(3) kJ mol^(-1)`

D

`- X_(4) kJ mol^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
B
Enthalpy of formation of `H_(2)O(l)` is
`H_(2)(g) + (1)/(2) O_(2)(g) = H_(2)O(l)`
:. `Delta H = - X_(2) kJ mol^(-1)`
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