Explanation:
(a)\(N{{a}_{2}}{{B}_{4}}{{O}_{7}}.10{{H}_{2}}O\xrightarrow[-10\,\,{{H}_{2}}O]{}N{{a}_{2}}{{B}_{4}}{{O}_{7}}\) \(\xrightarrow{\Delta }2NaB{{O}_{2}}+{{B}_{2}}{{O}_{3}}\)
\(CuO+{{B}_{2}}{{O}_{3}}\to \underset{(\text{Copper meta borate blue)}}{\mathop{Cu{{(B{{O}_{2}})}_{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}}\,\)