Question

The chemical formula of ice is:
A. ${{\text{O}}_{\text{2}}}$
B. ${{\text{H}}_{\text{2}}}\text{O}$
C. ${{\text{N}}_{\text{2}}}$
D. ${{\text{H}}_{\text{2}}}$

Answer 1

Hint: Recall what everyday chemical ice is a form of. Think about whether the conversion of water to ice is a chemical change or a physical change.

Complete step by step answer:
Let us start with the question of what ice is. Ice is a frozen form of water. The change of water to ice is a physical change. We know that when a physical change occurs in a substance, it does not affect the chemical formula and is reversible. Thus, ice will have the same chemical formula as water. We know that the chemical formula of water is ${{H}_{2}}O$.

Hence, the answer to this question is ‘B. ${{H}_{2}}O$’

Additional Information:
- Water exists in three phases as ice, water, and steam, which are in the states solid, liquid, and gaseous respectively.
- Hydrogen has 3 isotopes and all of them can combine with oxygen to form water. The isotope protium is the most widely found. Deuterium has an atomic mass number of 2 and contains a neutron along with a proton in the nucleus. Tritium has an atomic mass number of 3 and is a radioactive isotope of hydrogen.
- Water formed by the protium isotope will be denoted as ${{H}_{2}}O$, it is essential for the living, survival, and homeostasis of all living organisms.
- Water formed by the deuterium isotope will be denoted as ${{D}_{2}}O$ and is called heavy water. It does not have any immediate or life-threatening side effects, but consuming it in considerable amounts will lead to dizziness as the density will increase due to increased atomic weight.
- Water formed by the tritium isotope will be denoted as ${{T}_{2}}O$ and is called super-heavy water. It is a radioactive isotope and may cause mutations in the genes.
- When water freezes, the molecules should come closer together, but due to the bent shape of the molecules, small air pockets are formed. This reduces the density of ice drastically and causes ice to float on water.

Note:
Remember the fact that anything which changes the phase does not change the chemical composition. Whereas a chemical change will be irreversible and will bring about a change in the chemical composition as well as structure.