Which of the following is used as a catalyst for preparing a Grignard reagent?

Alkyl halides are prepared from alcohol by treating with:

By which reaction is Freon-$12$ manufactured from tetrachloromethane?

How many enantiomer pairs are obtained by monochlorination of $2, 3-$dimethylbutane?

By which reaction is Freon-$12$ $(CCl_2F_2)$ prepared from $CCl_4$?

Assertion : Alkyl iodide can be prepared by treating alkyl chloride/bromide with $NaI$ in acetone.
Reason : $NaCl/NaBr$ are soluble in acetone while $NaI$ is not.