Imagine a vertical tube of height h = 10 m filled with liquid mercury. The press
ID: 907930 • Letter: I
Question
Imagine a vertical tube of height h = 10 m filled with liquid mercury. The pressure exerted by such liquid column is calculated as p = rhogh, where rho is the liquid density and g = 9.81 m/s^ 2 is the gravitational acceleration constant. Suppose the temperature of the tube is lowered very slowly, making sure that at any instance T is uniform along the height of the column. As the freezing point of mercury is approached, will the solid phase of Hg begin to form first at the top or at the bottom of the tube? The density of Hg(l) is 13.5 g/cm^ 3 , while the density of Hg(s) is 14.1 g/cm 3 . Hg will freeze at the bottom first, due to the higher pressure. Hg will freeze at the top first, due to the low pressure. Hg will freeze at the bottom first, due to the higher entropy. Hg will freeze at the top first, due to the lower Gibbs free energy.Explanation / Answer
Hg will freeze at the top first, due to the low pressure
temperature is decreases pressure is decreases first top of mercury lower the temperature. so first freeze start at top