Convert 1 mm of hg into Pascal. Take density of hg= 13.6×10^3kg/m^3. g = 9.8m/s×s

1mm of hg pressure is supposed to be the extra pressured exerted by a column of mercury 1 mm high.  So the weight of the column of mercury =  density * height * Area * g               Area is the cross sectional area of the tube holding mercury.Pressure exerted by this column =  Weight / area              = density * height *  g             = 13.6 * 10³ kg /m³ * 1* 10^-3 m * 9.81 m/sec²                      = 133.416 Pascal  or Newton/meter² Height = 1mm (of mercury) column in the barometer.