Which of the following reactions defines Delt | vedclass

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(D) The standard enthalpy of formation,$\Delta H_f^o$,is defined as the enthalpy change when $1 \ mol$ of a substance is formed from its constituent e

Vedclass · Accepted Answer

$\frac{1}{2} H_{2(g)} + \frac{1}{2} F_{2(g)} 	o HF_{(g)}$

Vedclass · Answer

(D) The standard enthalpy of formation,$\Delta H_f^o$,is defined as the enthalpy change when $1 \ mol$ of a substance is formed from its constituent elements in their most stable standard states.In option $D$,$1 \ mol$ of $HF_{(g)}$ is formed from its elements $H_{2(g)}$ and $F_{2(g)}$ in their standard states.Option $A$ is incorrect because $H$ and $F$ are not in their standard states.Option $B$ is incorrect because $2 \ mol$ of $NH_3$ are formed.Option $C$ is incorrect because diamond is not the most stable standard state of carbon (graphite is).Therefore,the correct option is $D$.

Which of the following reactions defines $\Delta H_f^o$?

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