Which pair of liquids is most likely to be completely miscible?
- A. Water and petrol
- B. Water and ethanol
- C. Oil and water
- D. Mercury and water
Explanation
Ethanol has a hydroxyl group that hydrogen bonds with water, so the two mix in all proportions, illustrating the rule that like dissolves like. Petrol and oil are non polar hydrocarbons that cannot form such interactions with water and therefore separate into layers. Mercury is a liquid metal held by metallic bonding and is immiscible with almost everything.