The structural formulas for two isomers of 1, 2-dichloroethene are shown above. Which of the two liquids has the higher equilibrium vapor pressure at 20 degrees Celsius and why? A) the cis-isomer, because it has dipole-dipole interactions, whereas the trans-isomer has only 1 London dispersion forces.
B) the cis-isomer, because it has only London dispersion forces, whereas the trans-isomer also has dipole-dipole interactions
C) the trans-isomer, because it has dipole-dipole interactions, whereas the cis-isomer has only 1 London dispersion forces
D) the trans-isomer, because it has only 1 London dispersion forces, whereas the cos-isomer also has dipole-dipole interactions

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.