Question

The lattice energy of $NaCl$ is 788 kJ $mo{l}^{-1}$. This means that 788 kJ of energy is required:

• A. to separate one mole of solid $NaCl$ into one mole of $N{a}_{\left(g\right)}$ and one mole of $C{l}_{\left(g\right)}$ to infinite distance
• B. to separate one mole of solid $NaCl$ into one mole of $N{a}_{\left(g\right)}^{+}$ and one mole of $Cl{{}^{-}}_{\left(g\right)}$ to infinite distance
• C. to convert one mole of solid $NaCl$ into one mole of gaseous $NaCl$
• D. to convert one mole of gaseous $NaCl$ into one mole of solid $NaCl$

Answer 1

Answer: (B)

to separate one mole of solid $NaCl$ into one mole of $N{a}_{\left(g\right)}^{+}$ and one mole of $Cl{{}^{-}}_{\left(g\right)}$ to infinite distance

Here in the above image all the process to break the lattice is given and the sum of these energies is called lattice energy.

So the correct option is [B].