How radio telescopes to identify the chemical compounds that are present in interstellar clouds?

As explained below.

Explanation:

The radio telescope is a specialized antenna and receives the radio and emits radio waves in the sky and studies light waves patterns in the sky and are typically called as the parabolic antennas.The inter seller cloud is a composition of the dust and gases, plasma and as a radioactive matter, it radiates hat exists in the space and made up of the hydrogenized ions referring to the molecular clouds. Due to the electromagnetic radiation emitted from the clouds the antennas receive radio to visible to gamma rays of the spectrum and have EM radio have a longer wavelength and thus radio telescope can scan them at any point in time.