Consider a sample that is a mixture composed of biphenyl, benzoic acid, and benzyl alcohol. predict the order of elution of the components in this mixture. assume that the chromatography uses a silica column and the solvent system is based on cyclohexane, with an increasing proportion of methylene chloride added as a function of time.

biphenyl, benzyl alcohol, benzoic acid

Explanation:

Due to the nonpolar nature of cyclohexane, biphenyl will be the first solute to be eluted due to the presence of two phenyl rings. The second solute to be eluted will be benzyl alcohol due to the presence of OH group. This is because it has the ability to exhibit hydrogen bond with the silica column of the chromatography. Lastly, the benzoic acid will be the third solute to be eluted due to the presence of COOH group which is more polar than the OH group. Therefore, the order of elution of the components in the mixture is biphenyl, benzyl alcohol, benzoic acid.

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.

under a microscope, cancer cells may look very different from normal cells. they often have different sizes and some may be larger than normal while others are smaller. cancer cells are often abnormally shaped and the control centre of the cell (the nucleus) may have an abnormal appearance.

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