It is counted as a standard laboratory method for determining the molecular weight of a volatile liquid. This concept was discovered by Victor Meyer. In this process, a known mass of volatile liquid or solid is put under examination and they are converted into its vapor form by heating by using Victor Meyers tube, as this tube helps in the conversion of volatile solid or liquid into vapour form. Vapor helps in the displacement of its own volume of air and the volume of air displaced at given experimental temperature and pressure is calculated. At STP ( standard temperature pressure ) i.e at 2.24x10−2m3 displaced mass of air is calculated. The value which is obtained from this process is known as the molecular mass of the substance.
Instrumentation of this process includes an inner Victor Meyer's tube, the lower end of which is in the form of a bulb. The upper end of the tube has a side tube that leads to a trough filled with water. The tube which is known to be Victor Meyer’s tube is surrounded by a jacket from outside and a liquid is placed in an outer jacket, which usually boils at least 30k more than the substance when kept under examination. Usage of Meyers tube is used to protect instrument from outer breakage, when a glass bottle containing the substance under examination is dropped to it
Numerical Representation of Victor Meyer Method
This method is used for the determination of the molecular mass of volatile organic compounds. Under this process, we take the known mass of the compound, and this compound is vaporized in an instrument known as Victor Meyer tube. The amount of vapor obtained is measured and reduced to standard temperature pressure i.e STP.
Let the volume of vapors obtained at STP be V mL
22400 mL of vapors are obtained from 1 mole of a given compound.
V mL of vapors are obtained from (V/ 22400) mL of the compound
W/Mw = V/22400
Applications of Victor Meyer Method
1. Identification of Alcohols
This method is used for the identification of alcohol. From this, you can determine primary, secondary and tertiary alcohols by a change in their colors. During this process, alcohol is treated with Phosphorus triiodide which is further treated with Silver nitric oxide to get nitroalkane as a product. Further, this product i.e nitroalkane is treated with nitrous acid which is obtained by reaction of NaNO2 and HCl. The last wrestling solution is treated with KOH and the required color is obtained. If it is red the color indicates primary alcohol, if blue it indicates secondary alcohol and if no color is seen then indicates tertiary alcohol.
2. Determination of Empirical Formula and Molecular Formula
This method is used for the determination of both empirical as well as molecular formula, by using the given method. An empirical formula tells us the relative ratios of different atoms in a compound.
Whereas to find a molecular formula, we need to know the molecular mass of the given compound.
One Word Answer
1. Mercury forms a compound with chlorine that is 73.9% mercury and 26.1% chlorine by mass. What is the empirical formula?
Answer: Mercury dichloride
2. Which color is obtained in secondary alcohol during the alcohol detection?
Answer: Blue color