Question

For which of the following reaction ΔS is negative?
(a) Mg (s) + Cl₂ (g) → MgCl₂ (s)
(b) H₂O (I) → H₂O (g)
(c) CaCO₃ (s) → CaO (s) + CO₂ (g)
(d) I₂ (g) → 2I (g)

Answer 1

the option a is correct

Answer 2

(a) Mg (s) + Cl₂ (g)  →   MgCl₂ (s).

ΔH is negative and ΔS is negative so ΔG are negative at low temperatures.

ΔH is positive and ΔS is negative, ΔG does not negative at any temperature.

It has no spontaneous reaction.

When ΔH is positive and ΔS is positive, ΔG will be negative at high temperatures