question_answer 1)

  When the first element of the periodic table is treated with dioxygen, it gives a compound whose solid state floats on its liquid state. This compound has an ability to act as an acid as well as a base. What products will be formed when the compound undergoes auto ionisation?

Answer:

  The first element of periodic table is hydrogen. It reacts with oxygen and forms water. The solid state of water, i.e., ice floats on liquid water as it has lower density than liquid water. Water acts as an acid as well as base. Water behaves as an acid towards ammonia and behaves as a base towards hydrochloric acid. \[\underset{Base}{\mathop{N{{H}_{3}}}}\,+\underset{Acid}{\mathop{{{H}_{2}}O}}\,\to \underset{Acid}{\mathop{NH_{4}^{+}(aq)}}\,+\underset{Base}{\mathop{O{{H}^{-}}(aq)}}\,\] \[\underset{Acid}{\mathop{HCl}}\,+\underset{Base}{\mathop{{{H}_{2}}O}}\,\to \underset{Base}{\mathop{C{{l}^{-}}(aq)}}\,+\underset{Acid}{\mathop{{{H}_{3}}{{O}^{+}}(aq)}}\,\] In the autoionisation, acid, base are formed. \[\underset{Acid}{\mathop{{{H}_{2}}O}}\,+\underset{Base}{\mathop{{{H}_{2}}O}}\,\to \underset{\begin{smallmatrix}  Acid \\  Hydronium  \\  ion \end{smallmatrix}}{\mathop{{{H}_{3}}{{O}^{+}}}}\,+\underset{\begin{smallmatrix}  Base \\  Hydroxyl  \\  ion \end{smallmatrix}}{\mathop{O{{H}^{-}}}}\,\]