Gram staining is a fundamental and most widely employed microscopic staining method in bacteriology.
It is a differential stain, meaning it categorizes bacteria into two large groups based on their physical and chemical properties:
This classification is crucial for the initial identification of microorganisms and guides subsequent diagnostic procedures and treatment strategies. Its effectiveness and simplicity make it a standard technique in virtually all microbiology laboratories worldwide.
While other staining methods exist (like Acid staining or specific stains like Safranin, which is part of the Gram procedure), none are as universally applied for initial bacterial characterization as Gram staining.
| List-I | List-II |
| Electronic Configuration | First Ionisation energy (kJ mol$^{-1}$) |
| (A). ns$^2$ | (I). 2100 |
| (B). ns$^2$np$^1$ | (II). 1400 |
| (C). ns$^2$np$^3$ | (III). 800 |
| (D). ns$^2$np$^6$ | (IV). 900 |
| List-I | List-II |
| Spectroscopy | Property |
| (A). Raman | (I). Polarizability |
| (B). FTIR | (II). Dipole Moment |
| (C). UV-Visible | (III). Absorbance |
| (D). NMR | (IV). Spin |