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 (1) and (2) but no bonds are broken in reaction (1) whereas bonds in the reactant molecules are broken in reaction (2). As energy is absorbed when bonds are broken, energy released (1) is greater than that in reaction (2) hence, `x gt y`