Question

For the gas-phase decomposition
$PC{l}_5\left(g\right)\stackrel{△}{\rightleftharpoons }PC{l}_3\left(g\right)+C{l}_2\left(g\right):$

• A. $△H<0,△S<0$
• B. $△H>0,△S>0$
• C. $△H>0,△S<0$
• D. $△H<0,△S>0$

Answer 1

The correct option is B $△H>0,△S>0$

Because heat is absorbed in the reaction it is endothermic in nature So, $△H$ is positive
As the Number of gaseous moles increases on decomposition so entropy will increase. Thus $△S$ is also positive.