Question

If `Delta H_(f)^(@)` for `Ag^(+)` (infinitely diluted), `NO_(3)^(-)` (infinitely diluted), `Cl^(-)` (infinitely diluted) and `AgCl(s)` are `10.5 .579-207.36, -67.159` and `-127.068` respectively. Calculate the enthalpy change for the reaction
`AgNO_(3)(aq.)rarr+HCl(aq.)rarrAgCl(s)+HNO_(3)(aq.)`
A. `21.471 KJ//mol`
B. `145.688 KJ//mol`
C. `-65 488KJ//mol`
D. None

Answer 1

Correct Answer - C
`DeltaH_("reaction")^(@)=[DeltaH_(f)(AgCl)+DeltaH_(f)(H^(+))+DeltaH_(f)(NO_(3)^(-))]`
`-[DeltaH_(f)^(@)(Ag^(+))+DeltaH_(f)^(@)(NO_(3)^(-))]`
`-[DeltaH_(f)^(@)(Ag^(+))+DeltaH_(f)^(@)(NO_(3)^(-))]+DeltaH_(f)^(@)(Cl^(-))+DeltaH_(f)^(@)(H^(+))]`
`=-127.068-[105.579-167.159]= -65.488KJ//mol`.