When a raw egg is soaked in fresh lemon juice, the reaction can be same to the reaction happens when a raw egg is soaked in enough quantity of vinegar solution. The egg shell gets dissolved due to the reaction with acid in lemon juice and forms calcium citrate. As soon as the reaction starts between acid in lemon juice and calcium carbonate in egg shell, bubbles are formed immediately and the bubble foam is builds up around the shell, making the egg membrane soft and visible.