an iron piece floats on mercury ,but sinks in water .give reason.

1. A iron piece floats on the surface of mercury due to the combination of buoyant force and surface tension. The density of steel usually ranges between 7.75 and 8.05 g/cm³ and the density of mercury is 13.534 g/cm³.

As the density of mercury is greater then the density or iron thus iron floats in mercury.