How to remove the coin from Centrale puzzle? #shorts

Ag is removed electrolyticaly from 20cc of a 0.1 N solution of AgNO_(3) by a current of 0.1 amp. How long will it take to remove half of the silver from the solution?

Silver is removed electrolytically from 200mL of a 0.1N solution of AgNO_(3) by a current of 0.1A . How long will it take to remove half of the silver from the solution ?

How can we remove moisture from glass apparatus?

An electron in to be removed from the first energy level of hydrogen atom .How much energy is required for this purpose ?

Iron is removed from cahalcopyrite as