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JEE · NEET Previous Year Question

$The species which by definition has ZERO standard molar enthalpy of formation at 298 K is :$

Topic: JEE PYQ

Answer: B. Full step-by-step solution below.

A $B r_{2} (g)$
B $C l_{2} (g)$
C $H_{2} O(g)$
D $C H_{4} (g)$

Correct answer: B

Solution

(b) D H_{f} ° (C l_{2}, g) = 0, As D H_{f} ° of elements in their standard state is taken to be zero.

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