Which two molecules are compounds? nahco3 o3 cl2 c8h18

Answer : The correct options are, and

Explanation :

Molecules of element : It is defined as a pure substance that is composed of atoms of similar elements.

For example :  etc.

Molecule of compound : It is defined as a pure substance that is made from atoms of different elements combined together in a fixed ratio by mass.

For example :

Form the given options, and are the compounds. While the other options, and are the molecule of elements.

Hence, the correct options are, and

the real answer is b. scintillation counter