The species which by definition has zero standard molar enthalpy of formation at 298 K is

Options

A. `Br_(2)(g)`
B. `Cl_(2)(g)`
C. `H_(2)O(g)`
D. `CH_(4)(g)`

Answer

B

Explanation

At standard conditions, chlorine is found in gaseous form and bromine as in liquid form. And `DeltaH_f^@` of elements is taken as zero.