Question

For the reaction, $2Cl\left(g\right)\to C{l}_2\left(g\right),$ the correct option is

• A. ${\Delta }_{r}H>0$ and ${\Delta }_{r}S<0$
• B. ${\Delta }_{r}H<0$ and ${\Delta }_{r}S>0$
• C. ${\Delta }_{r}H<0$ and ${\Delta }_{r}S<0$
• D. ${\Delta }_{r}H>0$ and ${\Delta }_{r}S>0$

Answer 1

The correct option is C ${\Delta }_{r}H<0$ and ${\Delta }_{r}S<0$

$2Cl\left(g\right)\to C{l}_2\left(g\right)$

Atoms forming a molecule, making system less disordered. Entropy is decreasing $\Delta S(-ve)$ in the reaction. Further the addition reaction is exothermic since a bond is being formed, therefore $\Delta H$ is also -ve.