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Which of the following statement is true : -
A
Silicon exhibits 4 coordination number in its compound
B
Bond energy of $F_2$ is less than $Cl_2$
C
Mn(III) oxidation state is more stable than Mn(II) in aqueous state
D
Elements of 15th group show only +3 and +5 oxidation states
Detailed Solution
Bond dissociation enthalpies: $F_2$ about 158 kJ/mol and $Cl_2$ about 242 kJ/mol. So the bond energy of $F_2$ is less than that of $Cl_2$; this is true.
The F–F bond is weak because the F atoms are very small, so the lone pairs on the two atoms are close together and repel each other strongly.
Silicon can show coordination number 6 as well (e.g. $[SiF_6]^{2-}$), because of its vacant d orbitals, so it does not always show 4.
$Mn^{2+}$ ($3d^5$, half-filled) is more stable than $Mn^{3+}$ in water; $Mn^{3+}$ disproportionates.
Group 15 elements show oxidation states from –3 to +5, not only +3 and +5.
So the true statement is that the bond energy of $F_2$ is less than that of $Cl_2$.
The F–F bond is weak because the F atoms are very small, so the lone pairs on the two atoms are close together and repel each other strongly.
Silicon can show coordination number 6 as well (e.g. $[SiF_6]^{2-}$), because of its vacant d orbitals, so it does not always show 4.
$Mn^{2+}$ ($3d^5$, half-filled) is more stable than $Mn^{3+}$ in water; $Mn^{3+}$ disproportionates.
Group 15 elements show oxidation states from –3 to +5, not only +3 and +5.
So the true statement is that the bond energy of $F_2$ is less than that of $Cl_2$.