Standard heat of formation (Δ H fo) of different oxides of third period are given below Oxide Δ H fo( kJ m o l -1) Na2O -416 MgO -602 Al2O3 -1676 SiO2 -911 P4O10 -2984 SO3 -395 Most stable oxide is

Question

Standard heat of formation (Δ H fo) of different oxides of third period are given below Oxide Δ H fo( kJ m o l -1) Na2O -416 MgO -602 Al2O3 -1676 SiO2 -911 P4O10 -2984 SO3 -395 Most stable oxide is (A) MgO (B) Na2O (C) P4O10 (D) SO3

Tardigrade Admin · Accepted Answer

MgO is most stable Stability is based on the Δ H fo value per oxygen atom. Most negative value of Δ H fo per oxygen atom indicates most stable oxide.

Q. Standard heat of formation $(Δ H_{f}^{o})$ of different oxides of third period are given below

Oxide $Δ H_{f}^{o} (k J m o l^{- 1})$

$N a_{2} O$ -416

MgO -602

$A l_{2} O_{3}$ -1676

$S i O_{2}$ -911

$P_{4} O_{10}$ -2984

$S O_{3}$ -395

Most stable oxide is

$M g O$

$N a_{2} O$

$P_{4} O_{10}$

$S O_{3}$

$M g O$ is most stable

Stability is based on the $Δ H_{f}^{o}$ value per oxygen atom. Most negative value of $Δ H_{f}^{o}$ per oxygen atom indicates most stable oxide.

Oxide	$Δ H_{f}^{o} (k J m o l^{- 1})$
$N a_{2} O$	-416
MgO	-602
$A l_{2} O_{3}$	-1676
$S i O_{2}$	-911
$P_{4} O_{10}$	-2984
$S O_{3}$	-395

Q. Standard heat of formation (ΔHfo​) of different oxides of third period are given below Oxide ΔHfo​(kJmol−1) Na2​O -416 MgO -602 Al2​O3​ -1676 SiO2​ -911 P4​O10​ -2984 SO3​ -395 Most stable oxide is

MgO

Na2​O

P4​O10​

SO3​