Question

The following are the processes occurring during flame atomization in atomic absorption spectrometry:
(i) Volatilization (ii) Ionization
(iii) Nebulization (iv) Desolvation 
(v) Dissociation 
Arrange the processes in sequential order and choose the correct answer from below:

• A. (iii), (ii), (i),(iv), (v)
• B. (iii), (iv), (v), (ii), (i)
• C. (i), (iii), (iv),(ii), (v)
• D. (iii), (iv), (i), (v), (ii)

Answer 1

The Correct Option is D

To accurately arrange the processes involved in flame atomization in atomic absorption spectrometry, we first need to understand each step's role in the sequence:

1. Nebulization: The sample solution is converted into a fine aerosol mist. This is the first step as the sample must be prepared in such a fine mist to be introduced into the flame.
2. Desolvation: The solvent in the aerosol droplets is evaporated, leaving behind dry solute particles. This step follows nebulization to prepare the sample for further atomization.
3. Volatilization: The dry solute particles are then vaporized to form free atoms (or molecules) in the gas phase. This needs to happen after the solvent has been removed.
4. Dissociation: After volatilization, molecules in the vapor can dissociate into free atoms, which are necessary for atomic absorption spectrometry.
5. Ionization: Finally, some of the atoms may ionize. However, ionizing too many atoms can affect absorption measurement, and often, conditions are adjusted to minimize this process for accurate readings.

Thus, putting these processes in the correct sequence gives us: (iii) Nebulization, (iv) Desolvation, (i) Volatilization, (v) Dissociation, (ii) Ionization.

The correct answer is: (iii), (iv), (i), (v), (ii).

This sequence ensures a properly prepared sample for accurate atomic absorption spectrometry, addressing both physical and chemical steps needed to measure the concentration of elements accurately.