question_answer 54)

  The empirical formula and molecular mass of a compound are \[C{{H}_{2}}O\] and 180 g respectively. What will be the molecular formula of the compound? (a) \[{{C}_{9}}{{H}_{18}}{{O}_{9}}\]                          (b) \[C{{H}_{2}}O\] (c) \[{{C}_{6}}{{H}_{12}}{{O}_{6}}\]                          (d) \[{{C}_{6}}{{H}_{4}}{{O}_{2}}\]

Answer:

  (c) Molecular formula = \[{{(C{{H}_{2}}O)}_{n}}\] \[n=\frac{\text{Molecular mass}}{\text{Empirical formula mass }\!\!~\!\!\text{ }}=\frac{180}{30}=6\] \[\therefore \] Molecular formula = \[{{(C{{H}_{2}}O)}_{6}}={{C}_{6}}{{H}_{12}}{{O}_{6}}\]