Standard enthalpies of formation of O3,CO2,NH3 and HI are 142.2, -393.2, -46.2 and +25.9 kJmol- 1 respectively. The order of their increasing stabilities will be

Question

Standard enthalpies of formation of O3,CO2,NH3 and HI are 142.2, -393.2, -46.2 and +25.9 kJmol- 1 respectively. The order of their increasing stabilities will be (A) O3,CO2,NH3,HI (B) CO2,NH3,HI,O3 (C) O3,HI,NH3,CO2 (D) NH3,HI,CO2,O3

Tardigrade Admin · Accepted Answer

(i) Exothermic compounds are more stable than endothermic compounds. (ii) Greater is the amount of heat evolved in the formation of a compound, more will be its stability.

Q. Standard enthalpies of formation of $O_{3}, C O_{2}, N H_{3}$ and HI are 142.2, -393.2, -46.2 and +25.9 $k J m o l^{- 1}$ respectively. The order of their increasing stabilities will be

$O_{3}, C O_{2}, N H_{3}, H I$

$C O_{2}, N H_{3}, H I, O_{3}$

$O_{3}, H I, N H_{3}, C O_{2}$

$N H_{3}, H I, C O_{2}, O_{3}$

(i) Exothermic compounds are more stable than endothermic compounds.
(ii) Greater is the amount of heat evolved in the formation of a compound, more will be its stability.

Q. Standard enthalpies of formation of O3​,CO2​,NH3​ and HI are 142.2, -393.2, -46.2 and +25.9 kJmol−1 respectively. The order of their increasing stabilities will be

O3​,CO2​,NH3​,HI

CO2​,NH3​,HI,O3​

O3​,HI,NH3​,CO2​

NH3​,HI,CO2​,O3​