1. Tardigrade
  2. Question
  3. Chemistry
  4. Reaction of gaseous fluorine ( F 2) with compound X yields a single product Y, whose mass percent composition is 61.7 % F and 38.3 % Cl. Calculate Δr H° (in kJ / mol ) for the synthesis of Y using following information. 2 ClF ( g )+ O 2( g ) longrightarrow Cl 2 O ( g )+ OF 2( g ) Δ H °=205.6 kJ 2 ClF 3( g )+2 O 2( g ) longrightarrow Cl 2 O ( g )+3 OF 2( g ) Δ H °=533.0 kJ Δ f H °( OF 2, g )=24.7 kJ / mol

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Q. Reaction of gaseous fluorine $\left( F _{2}\right)$ with compound $X$ yields a single product $Y$, whose mass percent composition is $61.7 \% F$ and $38.3 \% Cl$.
Calculate $\Delta_{r} H^{\circ}$ (in $kJ / mol$ ) for the synthesis of $Y$ using following information.
$2 ClF ( g )+ O _{2}( g ) \longrightarrow Cl _{2} O ( g )+ OF _{2}( g ) $
$\Delta H ^{\circ}=205.6 \,kJ $
$2 ClF _{3}( g )+2 O _{2}( g ) \longrightarrow Cl _{2} O ( g )+3 OF _{2}( g ) $
$\Delta H ^{\circ}=533.0 \,kJ$
$\Delta_{ f } H ^{\circ}\left( OF _{2}, g \right)=24.7\, kJ / mol$

Thermodynamics

Solution:

$Cl$ :- no. of moles $\frac{38.7}{35.5}=1.09 $
$F:- \frac{61.7}{19}=3.42$
Simplest relative ratio $1: 3$
So, product $Y$ is $ClF _{3}$ \& compound $X$ is $ClF$
For the synthesis of $Y$ reaction is
$ F _{2}( g )+ ClF ( g ) \longrightarrow ClF _{3}( g ) $
$1 / 2 Cl _{2} O ( g )+3 / 2 OF _{2}( g ) \longrightarrow ClF _{3}( g )+ O _{2}( g )$
$\Delta H ^{\circ}=-533.0 / 2\, kJ \Rightarrow-266.5 \,kJ $
$ C / F ( g )+1 / 2 O _{2}( g ) \longrightarrow 1 / 2 Cl _{2} O ( g )+1 / 2 OF _{2}$
$\Delta H ^{\circ}=205.6 / 2\, kJ \Rightarrow 102.8 \,kJ$
$\frac{ F _{2}( g )+\frac{1}{2} O _{2}( g ) \longrightarrow F _{2} O ( g ) \Delta H ^{\circ}=24.7\, kJ }{ C / F ( g )+ F _{2}( g ) \longrightarrow C / F _{3}( g ) \cdot \Delta_{ f } H ^{\circ}=-139 \,kJ / mol }$