To solve the question "Which of the following statement is true?", we will analyze each statement provided:
1. **Silicon exhibits 4 coordination number in its compound.**
- Silicon typically exhibits a coordination number of 4 in many of its compounds, such as in silicon dioxide (SiO2) and silicates. However, it can also exhibit a coordination number of 6 in some complexes. Therefore, this statement is **not true**.
2. **Bond energy of F2 is less than Cl2.**
- The bond energy of F2 is indeed less than that of Cl2. This is because fluorine atoms are highly electronegative, which leads to significant repulsion between the lone pairs of electrons in the F-F bond, resulting in a weaker bond compared to Cl-Cl. Hence, this statement is **true**.
3. **Mn3 oxidation state is more stable than Mn2 in aqueous state.**
- In aqueous solutions, Mn2+ is more stable than Mn3+. The Mn2+ ion has a half-filled d orbital configuration (3d5), which provides extra stability. In contrast, Mn3+ has a 3d4 configuration, which is less stable. Therefore, this statement is **not true**.
4. **Elements of 15th group show only plus 3 and plus 5 oxidation states.**
- The elements of group 15 (such as nitrogen, phosphorus, arsenic, etc.) can exhibit oxidation states of -3, +3, and +5. The statement incorrectly implies that they only show +3 and +5 states. Hence, this statement is **not true**.
After analyzing all the statements, we conclude that the only true statement is:
**Correct Answer: Bond energy of F2 is less than Cl2.**
