Which among the following solids shows Frenkel defect?

A cold drink bottle contains 200 mL liquid, in which $\mathrm{CO}_2$ is 0.1 molar. Considering $\mathrm{CO}_2$ as an ideal gas the volume of the dissolved $\mathrm{CO}_2$ at S.T.P is

In the reaction,

$2 n R-X \xrightarrow[\text { Dry ether }]{+2 n \mathrm{Na}}$ product

The product obtained is

The bacteriostatic antibiotic from the following is