The octahedral diamagnetic low spin complex among the following is :

Using column chromatography, mixture of two compounds 'A' and 'B' was separated. 'A' eluted first, this indicates 'B' has

Given

$$\mathrm{\Delta H^0}$$ for the reaction

$$\mathrm{C(graphite)+\frac{1}{2}O_2(g)\to CO(g)}$$ is :

Isomeric amines with molecular formula C$$_8$$H$$_{11}$$N give the following tests

Isomer (P) $$\Rightarrow$$ Can be prepared by Gabriel phthalimide synthesis

Isomer (Q) $$\Rightarrow$$ Reacts with Hinsberg's reagent to give solid insoluble in NaOH

Isomer (R) $$\Rightarrow$$ Reacts with HONO followed by $$\beta$$-naphthol in NaOH to give red dye.

Isomers (P), (Q) and (R) respectively are