question_answer 110)

  How can \[{{D}_{2}}O\] be prepared from water? Mention the physical properties in which \[{{D}_{2}}O\] differs from\[{{H}_{2}}O\]. Give at least three reactions of \[{{D}_{2}}O\] showing the exchange of hydrogen with deuterium.

Answer:

  For preparation of heavy water, there is exhaustive distillation of ordinary water. It is a multistep distillation process. Physical properties  

		\[{{H}_{2}}O\]	\[{{D}_{2}}O\]
1.	Boiling point	373 K	374.42 K
2.	Melting point	273 K	276.82 K
3.	Mol. mass	18.016	20.03

                 Exchange reactions \[NaOH+{{D}_{2}}O\underset{{}}{\leftrightarrows}NaOD+HDO\] \[HCl+{{D}_{2}}O\underset{{}}{\leftrightarrows}DCl+HDO\] \[N{{H}_{4}}Cl+4{{D}_{2}}O\underset{{}}{\leftrightarrows}N{{D}_{4}}Cl+4HDO\]