Question

The enthalpy and entropy change for the reaction : Br2(l) + Cl2(g) → 2BrCl(g) are 30 kJ mol-1 and 105 JK-1 mol-1 respectively. The temperature at which the reaction will be in equilibrium is :

• A. 285.7 K
• B. 373 K
• C. 250 K
• D. 400 K

Answer 1

Answer: (A)

285.7 K

Answer 2

Correct option is A)
Br2​(l)+Cl2​(g)$\rightarrow$2BrCl(g)

△H=30KJ/mol=30×103J/mol

△S=105J/K/mol

Since, △G=0, then only system is at equilibrium.

So, △G=△H−T△S

At equilibrium, △H=T△S

Teq​=△S△H​=105$\times$30$\times$10​3=285.7K