Explanation

The phenomenon where a chemical element exists in multiple crystalline forms is called allotropy

Allotropy refers to the ability of an element to exist in two or more different forms in the same physical state.

This is different from polymorphism, which is a broader term referring to any substance (not just elements) that can exist in multiple crystalline forms. 

Explanation

 When iodine dissolves in water in the presence of KI, it forms the I₃⁻ ion.

Explanation

The pair that is not isomorphous is Na₂CO₃, CaCO₃. 

While both compounds have similar chemical formulas.

The difference in ionic radii between sodium and calcium leads to different crystal structures, making them not isomorphous.

Explanation

Rock candy is made by crystallizing sugar from a supersaturated solution using a seed crystal.

This process is known as the seedling technique, where crystals slowly grow over time.

Explanation

Physical changes (like melting, freezing, boiling) do not alter the substance's chemical composition.

They are usually easily reversible, unlike chemical changes.

Explanation

Natural rubber is classified as an elastomer, a type of polymer that can stretch and return to its original shape.

Elastomers are known for their elasticity and flexibility, making rubber ideal for tires, seals, and gloves.

Explanation

Hydrochloric acid (HCl) contains one ionizable hydrogen atom, which dissociates in water to form H⁺ and Cl⁻ ions.

It is classified as a monoprotic acid, meaning it donates only one proton (H⁺) per molecule.

Explanation

Alkali metals (like sodium and potassium) react vigorously with air and water, often catching fire.

To prevent this, they are stored in oil (like paraffin oil) to keep them stable and unreactive.

Explanation

 The common cultivated potato, Solanum tuberosum,

It has 48 chromosomes in its somatic cells (2n=4x=48).

This means it is a tetraploid species, with two sets of chromosomes derived from each of its two parents.

Therefore, the number of chromosomes in a potato's egg cell and in haploid somatic cells is 24. 

Explanation

The quantum number that describes the shape of an electron in an atom is the azimuthal quantum number (l).