For the chemical equilibrium,
`CaCO_(3)(s) hArr CaO(s)+CO_(2)(g)`
`Delta_(r)H^(ɵ)` can be determined from which one of the following plots?

Options

A.
B.
C.
D.

Answer

A

Explanation

`CaCO_(3)(s)hArrCaO(s)+CO_(2)(g)`
According to the law of chemical equilibrium,
`K_(p)=P_(CO_(2))` or `P_(CO_(2))//P^(o)`
where `P^(o)` is the reference pressure of 1 atm.
According to the van't Hoff equation,
In `((K_(T_(2)))/K_(T_(1)))=(Delta H^(o))/(R )((1)/(T_(1))-(1)/(T_(2)))`
for small temperature intervals where `Delta H^(o)` is essentially constant. Simplifled equation states that a plot of In K (or `2.303` log `P_(CO_(2)^(/P^(o))))` against `1//T` will be liner with a slope of `-Delta H^(o)//R`.