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TS EAMCET · Chemistry · Thermodynamics (C)

\(A B\) is an ionic solid. The ionic radii of \(A^{+}\)and \(B^{-}\) are respectively \(r_c\) and \(r_a\). Lattice energy of \(A B\) is proportional to :

  1. A \(\frac{r_c}{r_a}\)
  2. B \(\left(r_c+r_a\right)\)
  3. C \(\frac{r_a}{r_c}\)
  4. D \(\frac{1}{\left(r_c+r_a\right)}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\frac{1}{\left(r_c+r_a\right)}\)

Step-by-step Solution

Detailed explanation

The lattice becomes stronger (i.e., the lattice energy \(U\) becomes more negative), as \(r\) the inter ionic distance decreases. \(U\) is proportional to \(\frac{1}{r}\) or \(U \propto \frac{1}{\left(r_c+r_a\right)}\)