Answer:
they are molecules with normal bonds rather than partial bonds and can occasionally be isolated.
Explanation:
In chemistry, reaction intermediates are species that are formed from reactants and are subsequently being transformed into products as the reaction progresses. In other words, reaction intermediates are species that do not appear in a balanced reaction equation but occur somewhere along the reaction mechanism of a non-elementary reaction. They are usually short lived species that possess a high amount of energy. They may or may not be isolated.
They are often molecular species with normal bonds unlike activated complexes that are sometimes hypervalent species.
Put it in a beaker. Use a smaller beaker filled half way with ice and water and place in the larger one. It should be about an inch or two above the mixture. Heat over a Bunsen burner and the naphthalene will deposit on the bottom of smaller beaker.
And in this way, nephthalene be separated from the mixture of KBR and sand.
Chemical reactions can be identified when there is a change in color, energy is produced, change in odor, or if new substance forms.
Answer: The correct option is 3.
Explanation: We are given a compound which is made up of iron and oxygen only. The ratio of the two are given as:

This means that, number of iron ions are 2
Number of oxide ions are 3
From the above information, the formula becomes : 
The valency of iron = 3
Valency of oxide = 2
This compound is named as iron (III) oxide.
Hence, the correct option is 3