Question

What happens when the egg is first put in Hydrochloric acid for sometime and then placed in a concentrated salt solution?

Answer 1

The shell of the egg is composed of calcium carbonate crystals. Its chemical formula is $CaC{O_3}$ . The shell is a semi permeable membrane, through which air and moisture can pass through its pores. The shell also has a thin outermost covering known as the cuticle or bloom, which keeps out bacteria and dust.

Complete answer:
We are given two cases in the question. We’ll answer the cases one by one.
A) When the egg is put in Hydrochloric acid. The shell of the egg primarily consists of Calcium carbonate; hence we’ll consider this as the reaction between calcium carbonate and hydrochloric acid. The insides of the egg will not react with the HCl, only the shell will react, because it is the only react table component of the egg. The reaction between HCL and $CaC{O_3}$ can be given as:
$CaC{O_3} + HCl \to CaC{l_2} + C{O_2} + {H_2}O$
It forms Calcium Chloride and carbon dioxide is released in the form of bubbles in the reaction solution. The whole of the egg shell will dissolve in HCl leaving behind the York and the membrane covering.
B) The resulting egg is put in a salt solution. Here osmosis will take place, as the salt solution is Hypertonic (high concentration of solute) to the egg solution which is Hypotonic (Lower solute concentration). The concentration of water is higher inside the egg than that of outside. Exosmosis will take place, which means the water inside the egg will move to the outside through the semipermeable membrane. Due to this the size of the egg will reduce and it’ll shrink.

Note:
Osmosis is the movement of the solvent particles (mostly water) from a higher concentration to a lower concentration i.e., from a diluted solution to a concentrated solution. Here, the saline water is highly concentrated, the water moves from inside the shell to outside, through the membrane.