Assertion : Melting and boiling points of D_(2)O are higher than those of ordinary H_(2)O. Reason : D_(2)O has lesser degree of association and lower molecular mass than H_(2)O.

Assertion : Melting and boiling points of D_(2)O are higher than those

1.	Assertion : Melting and boiling points of D_(2)O are higher than those of ordinary H_(2)O. Reason : D_(2)O has lesser degree of association and lower molecular mass than H_(2)O.
Answer» If both assertion and reason are true and reason is the CORRECT explanation of assertion. If both assertion and reason are true but reason is not the correct explanation of assertion. If assertion is true but reason is false. If both assertion and reason are false. Solution :`D_(2)O` has higher molecular mass and greater DEGREE of association than `H_(2)O` and thus, has higher MELTING and BOILING POINTS.