CaQ and NaCI have the same crystal structure and approximately the same ionic radii. If U is the lattice energy of NaCl, the approximate lattice energy of CaO is

Options

A. U/2
B. U
C. 4U
D. 2U

Answer

C

Explanation

Lattice energy `=("Product of Charges")/("inter ionic distance")`
In NaCl the product of charges `=1 xx 1 `, In CaO product of charges `=2xx 2 =4` while the inter ionic distacne is almost same in both. Thus lattice energy of CaO is almost four times the lattice energy of NaCl.