In the Lucas test, tertiary alcohols form an oily layer of alkyl halide _.

Explanation

Option A: On heating is incorrect because heating is not required for the reaction to take place. The reaction occurs at room temperature. Option B: The Lucas test in alcohols is a test to differentiate between primary, secondary, and tertiary alcohols. Tertiary alcohols react immediately with the Lucas reagent as evidenced by turbidity owing to the low solubility of the organic chloride in the aqueous mixture. Option C: After 5-10 minutes is also incorrect because the reaction is very fast and occurs immediately. The turbidity or precipitation of the solution is typically observed within a few seconds to a minute after the addition of the Lucas reagent. Option D: After 20 minutes is also incorrect because the reaction is very fast and occurs immediately. The turbidity or precipitation of the solution is typically observed within a few seconds to a minute after the addition of the Lucas reagent.