Consider the reactions given below .On the basis of these reactions ,Find out which of the algebraic relations given in options (a) to(d) is correct?
`(p)C(g)+4H(g)toCH_(4)(g), Delta_(r)H=xKJ mol^(-1)`
`(Q)C("graphite")+2H_(2)(g)to CH_(4)(g),`
`Delta_(r)H=yKJmol^(-1)`

Options

A. x=y
B. `x= 2y`
C. `x gt y`
D. `x lt y`

Answer

C

Explanation

Same bonds are formed in reaction (i) and (ii) but no bonds are broken in reaction (i) where as bonds in the reactant molecules are broken in reaction (ii). As energy is absorbed when bonds are broken, energy released in reaction (i) is greater than that in reaction (ii) hence, x `gt` y.