• question_answer The substance which is solid at room temperature forms ionic compounds and reacts with hydrogen forming a hydride, the aqueous solution of which is acidic, could be A)  aluminium                  B)  sodium           C)  bromine                      D)  iodine

Hydride of AI and Na are basic while that of Br and I are acidic. But $B{{r}_{2}}$ is a liquid at room temperature and ${{I}_{2}}$ is a solid. Thus, the solid is iodine. ${{I}_{2}}+{{H}_{2}}\xrightarrow{\,}\,\underset{\begin{smallmatrix} \text{Hydrogen}\,\,\text{iodide}\, \\ \,\,\,\,\,\,\,\,\,\,\,\,\,\text{(acidic)} \end{smallmatrix}}{\mathop{2HI}}\,$