Some statements about heavy water are given below 

(1) Heavy water is more associated than ordinary water 

(2) Heavy water is used as a moderator in the nuclear reactor.

(3) Heavy water is better solvent than the ordinary water.

Which of the above statements are correct?

The degree of dissociation is higher for heavy water because its molecular mass is more than water. Therefore, it has higher boiling and melting point compared to ordinary water. Due to this reason, it is more associated that ordinary water.

Heavy water is used as a moderator because it slows down the neutrons without absorbing many neutrons. Hydrogen is not used as a moderator because it absorbs neutrons.

Dielectric constant of ordinary water is greater than the heavy water, ${\mathrm{H}}_2\mathrm{O}>{\mathrm{D}}_2\mathrm{O}.$ Therefore, the ordinary water is more effective solvent than the heavy water.