List of top Physics Questions on coulombs law asked in MET

In the reaction sequence $CH_{3}COOH \xrightarrow{LiAlH_{4}} X \xrightarrow{Cu, 300^{\circ}C} Y \xrightarrow{dil.\ NaOH} Z$, the final product Z is

Two identical spheres A and B have charge $q$ and are distance $r$ apart. A third identical uncharged sphere C is touched to B and placed at the midpoint. The force on C is: