Why is mercury not suitable as the liquid in the U-tube? (the relationship between density of the liquid and the pressure in the liquid)​

Mercury Is more suitable than water cause it is denser than water.

Relation between density and pressure

Pressure = force/area

Replace force by mass * acceleration
Pressure = mass * acceleration/ area

We can replace mass by density * volume since density = mass/ volume
Pressure = density * volume * acceleration/ area

Volume is length^3 whereas area is length ^2. So volume / area = length

Pressure = density * length * acceleration

Gravity is form of acceleration so

Pressure = density * length * gravity
Length can be height or depth

Finally pressure = density * height * gravity

P = ρ g h => pressure of liquid