The correct answer is hydrogen<span>, and </span>oxygen<span>. </span>
Heat energy is required.
In distillation, the solution is first heated, where heat energy is required, such as using a bunsen burner.
When the solution is heated, the water may reach its boiling point and evaporate. However, salt does not. When water molecules evaporates, it travels through a condenser that cools it down into liquid again. Therefore we get pure water. Salt is also obtained in the original beaker.
Therefore to first start this process, heat energy is required.
b) It is based on atomic properties as alkali metals requires 7 more electrons to complete their outer orbit. And they try to give those electrons to other elements to obtain noble gas configuration.
Noble gases are the gases which do not react easily with anything. They are also called as Inert gases, and belongs to group 18 of the periodic table.
Alkali metals are the substances which are found in Group I of a periodic table. Mostly the elements which are present are:
Properties of alkali metals are: Soft, shiny reactive metals. They are soft enough to cut with knife. Metals react with water and air quickly and gets tarnish, so pure metals are stored in container by dipping them in oil to prevent oxidation.
To know more about Alkali metals, refer to this link:
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Answer: 
Explanation:
Engineering notation : It is the representation of expressing the numbers that are too big or too small and are represented in the decimal form times 10 raise to the power. It is similar to the scientific notation but in engineering notation, the powers of ten are always multiples of 3.
The engineering notation written in the form:
where,
a = the number which is greater than 0 and less than 999
b = an integer multiple of 3
Now converting the given value of 2,469,100 into engineering notation, we get
Hence, the correct answer is,
<span>NaCn contains an Na+ ion and a CN- negative ion, so it has an ionic bond. The CN ion is formed by a covalent bond of the carbon and nitrogen, so it also has a covalent bond. Therefore, the answer is NaCN.</span>
