H 2+ Cl 2 longrightarrow 2 HCl , Δ H=-194 kJ In the above reaction the heat of formation of HCl is :

Question

H 2+ Cl 2 longrightarrow 2 HCl , Δ H=-194 kJ In the above reaction the heat of formation of HCl is : (A) + 97 kJ (B) - 97 kJ (C) + 107 kJ (D) - 107 kJ

Tardigrade Admin · Accepted Answer

Heat of formation is the amount of heat absorbed or liberated when one mole of a substance is formed from its constituent element.
When

2

moles of

H Cl

is formed heat liberated =

194 k J

∴

When

1 m o l

of

H Cl

is formed heat liberated

= \frac{194}{2} = 97 k J

∴ Δ H_{f} = - 97 k J

Q. H2​+Cl2​⟶2HCl,ΔH=−194kJ In the above reaction the heat of formation of HCl is :

+ 97 kJ

- 97 kJ

+ 107 kJ

- 107 kJ

Heat of formation is the amount of heat absorbed or liberated when one mole of a substance is formed from its constituent element. When 2 moles of HCl is formed heat liberated = 194kJ ∴ When 1mol of HCl is formed heat liberated =2194​=97kJ ∴ΔHf​=−97kJ

Q. $H_{2} + C l_{2} ⟶ 2 H Cl, Δ H = - 194 k J$ In the above reaction the heat of formation of $H Cl$ is :