Neither dry soil nor pure water conducts electricity. but wet soil will conduct electricity. explain why this happens?

Pure water does not have enough ions to conduct electricity. A mixture of metals such as iron, zinc and copper in the wet soil can trigger electrolysis that requires excess energy in the form of over potential to conduct electricity. The excess energy is needed due to limited self-ionization of water. The wet soil then can conduct current when positive and negative ions are present. The water ions begin to flow from anode (positive electrode) to cathode (negative electrode) to be oxidize and produce electricity.

 

B? i feel like this is a trick  

Molarity is moles of solute over liters of solution. idk if that is what you are talking about, but you can convert moles of solute to grams of solute using dimensional analyzes by using molar mass found on the periodic table.