Question

When ZnO lattice is heated, the formula of lattice becomes (x > 0) : (1) ZnO (2) Zn(1+x)O (3) ZnO(1+x) (4) Zn(1-x)O

Answer 1

The explanation for the correct option:

Option(3)$Z{n}_{1+x}O$

• The metal excess defect is a non-stoichiometric defect that occurs ​in crystals.
• A non-stoichiometric defect is a defect that does not affect the stoichiometry of the crystalline substance.
• As we know crystals are white. when they are heated, they lose one oxygen atom and turn yellow.

$ZnO⟶Z{n}^{2+}+\frac{1}{2}{O}_2+2e^{-}$

• Since, the crystals are white. when they are heated, they lose one oxygen atom, it now has an excess of zinc in them.
• hence the formula becomes ​$Z{n}_{1+x}O$ and the excess $Z{n}^{2+}$ ions formed to occupy the interstitial(vacant or empty) sites in the crystal.

Hence, Option(3) $Z{n}_{1+x}O$ is the formula of the lattice formed When the ZnO lattice is heated.