Question

From the following data, mark the option (s) where `DeltaH` is correctly written for the given reaction. Given:
`H^(+)(aq)+OH^(-) (aq) rarr H_(2)O(l)" "DeltaH= -57.3 kJ`
`DeltaH_("solution")` of `HA(g)= -70.7` kJ/mol
`Delta_("solution")` of `BOH(g)=20` kJ/mol
`DeltaH_("ionization")` of `HA=15` kJ/mol & `BOH` is a strong base
A. `{:("Reaction",DeltaH_(R)" (kJ/mole)"),(HA(aq)+BOH(aq) rarr BA(aq)+H_(2)O,-42.3):}`
B. `{:("Reaction",DeltaH_(R)" (kJ/mole)"),(HA(g)+BOH(g) rarr BA(aq)+H_(2)O,-93):}`
C. `{:("Reaction",DeltaH_(R)" (kJ/mole)"),(HA(g) rarr H^(+) (aq)+A^(-)(aq),-55.7):}`
D. `{:("Reaction",DeltaH_(R)" (kJ/mole)"),(B^(+)(aq)+OH^(-)(aq) rarrBOH(aq),-20):}`

Answer 1

Correct Answer - A::B::C
`HA(aq)+BOH(aq) rarr BA(aq)+H_(2)O`
`DeltaH=-57.3+DeltaH_("ion")HA`
`=-42.3` option (A) correct
`HA(g)+BOH(g) rarr BA(aq)+H_(2)O`
`DeltaH=DeltaH_("solution")HA+DeltaH_("solution")BOH-57.3+15`
`=-93` option (B) correct
`HA(g) rarr H^(+) (aq)+A^(-) (aq)`
`DeltaH=DeltaH_("solution")+DeltaH_("ions")=-55.7 kJ` option (C) is correct
`:. BOH` is strong base `:. DeltaH_("ion")=0`
`:. B^(+) (aq)+OH^(-)(aq) rarr BOH(aq) DeltaH=0`