As distilled water contains no minerals it is an insulator. when the contains minerals, it will have iron in it ( which is a conductor of electricity )

Vinegar is not a good conductor of electricity.

Explanation:

Introduction:
Conductors are materials that allow the flow of electric charge through them easily, while insulators are materials that do not allow the flow of electric charge. In this context, we will analyze the given options to identify the one that is not true.

Vinegar:
Vinegar is a liquid substance primarily composed of acetic acid and water. While it does contain ions, it is not a good conductor of electricity. The conductivity of a material depends on the concentration of ions and their mobility. Vinegar has a relatively low concentration of ions and does not provide a pathway for the movement of charge, making it a poor conductor of electricity.

Carbon rod as an electrode:
A carbon rod can function as an electrode, which is a conductor through which electric current enters or exits an electrolytic cell. Carbon is a good conductor of electricity and is commonly used in batteries, electrolytic processes, and other electrical applications.

LED:
An LED (Light Emitting Diode) is a semiconductor device that emits light when an electric current passes through it. LEDs are not conductors of electricity; rather, they are electronic components that convert electrical energy into light energy.

Distilled water:
Distilled water is water that has been purified through the process of distillation, which involves boiling the water and then condensing the steam. The distillation process removes impurities and minerals, resulting in highly pure water. Distilled water is an insulator because it does not contain significant amounts of ions or impurities that can facilitate the flow of electric charge.

Conclusion:
Out of the given options, the statement that is not true is option C: "LED is a conductor." LEDs are not conductors of electricity; they are electronic components that emit light when an electric current passes through them.