Explain what happens when boric acid is heated. 

Aluminium has a great affinity for oxygen and its oxidation is an exothermic process. This fact is made use of in

The element which exists in liquid state for a wide range of temperature and can be used for measuring high temperature is :- 

The reaction of $\mathrm{H}_{3} \mathrm{N}_{3} \mathrm{B}_{3} \mathrm{Cl}_{3}$ $(A)$ with $\mathrm{LiBH}_{4}$ in tetrahydrofurane gives inorganic benzene $(B)$. Further, the reaction of $(A)$ with $(C)$ leads to $\mathrm{H}_{3} \mathrm{N}_{3} \mathrm{B}_{3}(\mathrm{Me})_{3}$. than Compounds $(\mathrm{B})$ and $(\mathrm{C})$ respectively, are

$N{a_2}{B_4}{O_7}.10{H_2}O\xrightarrow{{Heat}}X + NaB{O_2} + {H_2}O,X + C{r_2}{O_3}\xrightarrow{{Heat}}\mathop Y\limits_{\left( {Green\,coloured} \right)} $ $X$ and $Y$ are