The increase in the atomic radii of the third (5d) series of transition elements is very small, which may be accounted for the filling of ' $X$ ' orbitals before ${ }^{\prime} Y^{\prime}$ orbitals $X$ and $Y$ are

A metal complex absorbed orange light. The colour in which it appears is

The major product of the following reaction is

$$ \text { Glucose } \frac{\text { (i) } \mathrm{HI}, \Delta}{\text { (ii) } \mathrm{Mo}_2 \mathrm{O}_3, 773 \mathrm{~K}, 10 \cdot 20 \mathrm{am}} $$

$$ \text { The major product in the following reaction is } $$