Question

Which of the following reactions will have the value of $\Delta S$ with a negative sign?

• A. $H_2O_{(l)} \to H_2O_{(g)}$
• B. $2SO_{2(g)} + O_{2(g)} \to 2SO_{3(g)}$
• C. $Cl_{2(g)} \to 2Cl_{(g)}$
• D. $CaCO_{3(s)} \to CaO_{(s)} + CO_{2(g)}$

Answer 1

Answer: (B)

$2SO_{2(g)} + O_{2(g)} \to 2SO_{3(g)}$
$\Delta n_g = 2 - 3 = -1$, $\Delta S = -ve$