Iron exhibits + 2 and +3 oxidation states. Which of the following statements about iron is incorrect?

In which of the following pairs the two species are not isostructural ?

Ortho–Nitrophenol is less soluble in water than p– and m– Nitrophenols because :

The electrons identified by quantum numbers n and l :
(a) n = 4, $$l$$ = 1
(b) n = 4, $$ l$$ = 0
(c) n = 3, $$l$$ = 2
(d) n = 3, $$l$$ = 1
Can be placed in order of increasing energy as :