Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?
Electronic configuration of Mn2+ is [Ar]1818 3d5 .
Electronic configuration of Fe2+ is [Ar]18 3d6 .
It is known that half-filled and fully-filled orbitals are more stable. Therefore, Mn in (+2) state has a stabled 5 configuration. This is the reason Mn2+ shows resistance to oxidation to Mn3+ . Also, Fe2+ has 3d6 configuration and by losing one electron, its configuration changes to a more stable 3d5 configuration. Therefore, Fe2+ easily gets oxidized to Fe+3 oxidation state.
A racing track is built around an elliptical ground whose equation is given by \[ 9x^2 + 16y^2 = 144 \] The width of the track is \(3\) m as shown. Based on the given information answer the following: 
(i) Express \(y\) as a function of \(x\) from the given equation of ellipse.
(ii) Integrate the function obtained in (i) with respect to \(x\).
(iii)(a) Find the area of the region enclosed within the elliptical ground excluding the track using integration.
OR
(iii)(b) Write the coordinates of the points \(P\) and \(Q\) where the outer edge of the track cuts \(x\)-axis and \(y\)-axis in first quadrant and find the area of triangle formed by points \(P,O,Q\).