Which among the following reactions is used for the preparation of alkyl fluorides?

What type of colloid is milk?

What is the osmotic pressure of solution prepared by dissolving 3 gram solute in $2 \mathrm{dm}^3$ water at 300 K . (Molar mass of solute $=60 \mathrm{~g} \mathrm{~mol}^{-1}$, $\mathrm{R}=0.0821 \mathrm{dm}^3 \mathrm{~atm} \mathrm{~K} \mathrm{~mol}^{-1})$

Which among the following is the method for the preparation of ethers?