Question

Which best describes a compound such as sodium chloride?

a pure substance that can be separated into different elements by physical means
a mixture of two common substances that can be separated by chemical means
a mixture of two common elements that can be separated by physical means
a pure substance that can be separated into different elements by chemical means

Answer 1

Answer: Option (d) is the correct answer.

Step-by-step explanation:

A compound is defined as a substance which contains two different atoms that chemically combine together in a fixed ratio by mass.

A compound can be broken down into its constituent particles.

Pure substances are defined as the species which contains same type of atoms.

For example, NaCl is a pure compound and it can be separated into sodium and chlorine elements.

Thus, we can conclude that the statement a pure substance that can be separated into different elements by chemical means, best describes a compound such as sodium chloride.

Answer 2

The second option is the answer. This is a mixture of two common substances that can be separated by chemical means.

NaCL is a compound that was formed through a chemical reaction between sodium and chlorine. In that reaction sodium which is a toxic metal combines with chlorine, a poisonous gas, to form a harmless but totally new compound NaCl or table salt.

Since the sodium ions have a positive charge and the chlorine ions have a negative charge, they are attracted to each other to form an ionic bond.

Sodium can only be separated from Chloride by chemical means e.g. electrolysis.