On the basic of thermochemical equations (I),(II)and (III), Find out which of the algebraic relationships given in options (a)to (d) is correct ?
(I)`C("graphite")+O_(2)(g)to CO_(2)(g),`
`Delta_(r)H=XKJmol^(-1)`
(II)`C("graphite")+(1)/(2)O_(2)(g)toCO(g),`
`Delta_(r)H=yKJ mol^(-1)`
`(III) CO(g)+(1)/(2)O_(2)(g)toCO_(2)(g), Delta_(r)H=zKJ mol^(-1)`

Options

A. `z= x+y`
B. `x= y-z`
C. `x= y+z`
D. `y= 2z- x`

Answer

C

Explanation

The algebraic relationships of the given reaction is equation (a)- equation (b) = equation (c)
(a) C(graphite) `+ O_(2)(g) rarr CO_(2)(g), Delta_(r)H= xkJ mol^(-1)`
(b) C(graphite) `+ (1)/(2) O_(2)(g) rarr CO(g), Delta_(r)H = ykJ mol^(-1)`
`bar(CO(g) + (1)/(2) O_(2)(g) rarr CO_(2)(g), Delta_(r)H= zkJ mol^(-1))`
Hence, `x-y=z or x= y+z`