The heat of formation of water is `260 kJ`. How much `H_(2)O` is decomposed by `130 kJ` heat ?

Options

A. `0.25` mol
B. 1 mol
C. `0.5` mol
D. 2 mol

Answer

C

Explanation

The reaction for the formation of water is as
`H_(2) + (1)/(2) O_(2) to H_(2) O , Delta H = 260 kJ … (i)`
On reversing Eq. (i) , we get
`underset(1 "mol")(H_(2)O) to H_(2) + (1)/(2)O_(2) , `
`Delta H = -260 kJ " " … (ii)`
`because` By 260 kJ heat water decomposed = 1 mol
`therefore` 130 kJ heat will decompose water = `(1 xx 130)/(260)`
= 0.5 mol