For the gas phase reaction, PCl 5( g ) leftharpoons PCl 3( g )+ Cl 2( g ) which of the following conditions are correct?

Question

For the gas phase reaction, PCl 5( g ) leftharpoons PCl 3( g )+ Cl 2( g ) which of the following conditions are correct? (A) Δ H = 0 and Δ S < 0 (B) Δ H > 0 and Δ S > 0 (C) Δ H < 0 and Δ S < 0 (D) Δ H > 0 and Δ S < 0

Tardigrade Admin · Accepted Answer

For the reaction PCl5 (g) leftharpoons PCl3 (g) + Cl2 (g) The reaction given is an example of decomposition reaction and we know that decomposition reactions are endothermic in nature, i.e, Δ H > 0. Further Δ n = (1 + 1) - 1= + 1 Hence more number of molecules are present in products which shows more randomness i.e. Δ S > 0 (Δ S is positive)

Q. For the gas phase reaction,
$PC l_{5} (g) ⇌ PC l_{3} (g) + C l_{2} (g)$
which of the following conditions are correct?

$Δ H = 0$ and $Δ S < 0$

$Δ H > 0$ and $Δ S > 0$

$Δ H < 0$ and $Δ S < 0$

$Δ H > 0$ and $Δ S < 0$

Q. For the gas phase reaction, PCl5​(g)⇌PCl3​(g)+Cl2​(g) which of the following conditions are correct?

ΔH=0 and ΔS<0

ΔH>0 and ΔS>0

ΔH<0 and ΔS<0

ΔH>0 and ΔS<0

Q. For the gas phase reaction,
$PC l_{5} (g) ⇌ PC l_{3} (g) + C l_{2} (g)$
which of the following conditions are correct?

$Δ H = 0$ and $Δ S < 0$

$Δ H > 0$ and $Δ S > 0$

$Δ H < 0$ and $Δ S < 0$

$Δ H > 0$ and $Δ S < 0$