Group 15 elements (such as nitrogen, phosphorus, arsenic, etc.) can form covalent bonds with other elements, and the maximum covalency typically corresponds to the number of bonds that can be formed.
For a non-metallic element in group 15, the maximum covalency is usually determined by the number of available orbitals for bonding.
- Nitrogen, the lightest element in Group 15, has the weakest E-E bond due to its small atomic size and high electronegativity, which limits the number of bonds it can form.
- Phosphorus, arsenic, and other heavier elements in the group can form a maximum of 4 bonds due to their larger atomic size and availability of d-orbitals for bonding.
Thus, the correct answer is that the maximum covalency for a non-metallic Group 15 element with the weakest E-E bond is 4.
| Column I | Column II |
| P. Solubility | i. Reverse phase chromatography |
| Q. Ionic charge | ii. Ultracentrifugation |
| R. Polarity | iii. Salting out |
| S. Molecular size | iv. Isoelectric focusing |
| v. Gel electrophoresis |
| Column I | Column II |
| P. Solubility | i. Reverse phase chromatography |
| Q. Ionic charge | ii. Ultracentrifugation |
| R. Polarity | iii. Salting out |
| S. Molecular size | iv. Isoelectric focusing |
| v. Gel electrophoresis |
Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?

Let \( \alpha = \dfrac{-1 + i\sqrt{3}}{2} \) and \( \beta = \dfrac{-1 - i\sqrt{3}}{2} \), where \( i = \sqrt{-1} \). If
\[ (7 - 7\alpha + 9\beta)^{20} + (9 + 7\alpha - 7\beta)^{20} + (-7 + 9\alpha + 7\beta)^{20} + (14 + 7\alpha + 7\beta)^{20} = m^{10}, \] then the value of \( m \) is ___________.