MCQ
${H_2}\left( g \right) + \frac{1}{2}{O_2}\left( g \right) \to {H_2}O\left( g \right)$
$B.E. (H-H) = x_1 ; B.E. (O = O) = x_2$ ;
$B.E. (O -H) = x_3$
Heat of vaporisation of water $= x_4$ then $\Delta {H_f}$ [heat of formation of liquid water] is
- A${x_1} + \frac{{{x_2}}}{2} - {x_3} + {x_4}$
- B$2{x_3} - {x_1}-\frac{{{x_2}}}{2} - {x_4}$
- ✓${x_1} + \frac{{{x_2}}}{2} - 2{x_3} - {x_4}$
- D${x_1} + \frac{{{x_2}}}{2} - 2{x_3} + {x_4}$
