Question

Orthoboric acid when heated to red hot gives:

• A. metaboric acid
• B. pyroboric acid
• C. boron and water
• D. diboron trioxide

Answer 1

Answer: (D)

${\text{H}}_{\text{3}}{\text{BO}}_{\text{3}}{\to }_{{\text{-H}}_{\text{2}}\text{O}}^{{\text{Δ/100}}^{\text{o}}\text{C}}{\text{HBO}}_{\text{2}}{\to }_{{\text{-160}}^{\text{o}}\text{C}}^{\text{Δ}}{\text{H}}_{\text{4}}{\text{B}}_{\text{2}}{\text{O}}_{\text{7}}{\to }_{\text{Red}\text{Hot }\text{>}{\text{250}}^{\text{o}}\text{C}}^{\text{Δ}}{\text{B}}_{\text{2}}{\text{O}}_{\text{3}}{\text{+2H}}_{\text{2}}\text{O}$