Diborane is a potential rocket fuel which undergoes combustion according to the reaction. B 2 H 6( g )+3 O 2 (g) longrightarrow B 2 O 3( s )+3 H 2 O ( g ) From the following data, calculate the enthalpy change for the combustion of diborane. 2 B ( s )+(3 / 2) O 2( g ) longrightarrow B 2 O 3 (s) Δ H =-1273 kJ mol -1 H 2( g )+(1 / 2) O 2( g ) longrightarrow H 2 O (l) Δ H =-286 kJ mol -1 H 2 O (l) longrightarrow H 2 O ( g ) Δ H =44 kJ mol -1 2 B ( s )+3 H 2( g ) longrightarrow B 2 H 6( g ) Δ H =36 kJ mol -1

Question

Diborane is a potential rocket fuel which undergoes combustion according to the reaction. B 2 H 6( g )+3 O 2 (g) longrightarrow B 2 O 3( s )+3 H 2 O ( g ) From the following data, calculate the enthalpy change for the combustion of diborane. 2 B ( s )+(3 / 2) O 2( g ) longrightarrow B 2 O 3 (s) Δ H =-1273 kJ mol -1 H 2( g )+(1 / 2) O 2( g ) longrightarrow H 2 O (l) Δ H =-286 kJ mol -1 H 2 O (l) longrightarrow H 2 O ( g ) Δ H =44 kJ mol -1 2 B ( s )+3 H 2( g ) longrightarrow B 2 H 6( g ) Δ H =36 kJ mol -1 (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

To get B 2 H 6( g )+3 O 2( g ) longrightarrow B 2 O 3( s )+3 H 2 O ( g ) (i) +3 (ii) + (iii) × 3- (iv) 2 B ( s )+3 / 2 O 2( g ) longrightarrow B 2 O 3( s ) Δ H =-1273 kJ / mol 3 H 2( g )+3 / 2 O 2( g ) longrightarrow 2 H 2 O ( l ) Δ H =3 × 286 kJ / mol 3 H 2 O (l) longrightarrow 3 H 2 O ( g ) ; Δ H =3 × 44 <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/6b187c49c236f2c419f4ee941ea85a97-.png" />

To get B2​H6​(g)+3O2​(g)⟶B2​O3​(s)+3H2​O(g) (i) +3 (ii) + (iii) ×3− (iv) 2B(s)+3/2O2​(g)⟶B2​O3​(s) ΔH=−1273kJ/mol 3H2​(g)+3/2O2​(g)⟶2H2​O(l) ΔH=3×286kJ/mol 3H2​O(l)⟶3H2​O(g);ΔH=3×44