KCl crystallizes int the same type of lattic as done NaCl . Given that `r_(Na^(+))//r_(Cl^(-)) = 0.50` and `r_(Na^(+))//r_(K^(+)) = 0.70` , Calcualte the ratio of the side of the unit cell for KCl to that for NaCl:

Explanation

To solve the problem of calculating the ratio of the side of the unit cell for KCl to that for NaCl, we will follow these steps:

### Step 1: Understand the relationship between the ionic radii and the unit cell dimensions.
In a rock-salt structure (like NaCl and KCl), the relationship between the ionic radii and the side length of the unit cell can be expressed as:
\[ A = 2R_{Na^+} + 2R_{Cl^-} \]
for NaCl, and
\[ A_2 = 2R_{K^+} + 2R_{Cl^-} \]
for KCl.
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