What will happen when egg shell is placed in Conc. HNO3?

When an eggshell is placed in concentrated nitric acid (HNO3), the following reactions occur:

1. The eggshell is primarily composed of calcium carbonate (CaCO3). When it comes into contact with concentrated nitric acid, a chemical reaction occurs, producing calcium nitrate, water, and carbon dioxide. The reaction can be represented as follows:

   CaCO3(s) + 2HNO3(aq) → Ca(NO3)2(aq) + H2O(l) + CO2(g)

2. The carbon dioxide gas (CO2) is released as bubbles, which is a visible sign of the reaction.

3. The calcium nitrate formed (Ca(NO3)2) remains in the solution.

4. The eggshell will dissolve in the acid due to the reaction, so if left for a sufficient amount of time, the eggshell will completely disappear.

Please remember to handle concentrated nitric acid with care as it is a strong acid and can cause burns. Always use appropriate personal protective equipment and work in a well-ventilated area.