ANS:D - all (a), (b) and (c)

The conductivity of a crude oil-water mixture primarily depends on water percentage. Here's an explanation:

1. Crude Oil-Water Mixture: When crude oil and water are mixed, the electrical conductivity of the mixture is primarily influenced by the presence of water.
2. Water Percentage: The conductivity of a solution (in this case, the crude oil-water mixture) is largely determined by the concentration of ions dissolved in the water. Crude oil itself is typically non-conductive or has very low conductivity due to its non-polar nature and minimal ionic content.
3. Factors Considered:
   • pH Value: Crude oil tends to be neutral in pH, and while pH can affect the ionic dissociation of substances in water, crude oil's influence on conductivity is minimal compared to the water content.
   • Temperature: Temperature can affect the conductivity slightly due to changes in the mobility of ions in the water phase, but its impact is secondary compared to water content.
   • Water Percentage: The more water present in the crude oil-water mixture, the higher the conductivity due to the increased concentration of ions (e.g., dissolved salts) in the water phase.
4. Conductivity Measurement: Conductivity is typically measured using a conductivity meter, which detects the ability of the solution to conduct an electric current. Higher conductivity indicates a higher concentration of dissolved ions, usually from water.

Therefore, while pH value and temperature can influence conductivity to some extent, the primary factor that affects the conductivity of a crude oil-water mixture is the water percentage. More water leads to higher conductivity due to increased ion concentration in the water phase.