# Why D_2O is hydrophobic in nature?

${D}_{2} O$ is NOT a hydrophobe.
${D}_{2} O$, i.e. ""^2H_2O, is an isotopomer of water. Water and heavy water would be infinitely miscible. Certainly, if you are a big enough pratt to leave your bottle of heavy water open, it will exchange protons with atmospheric water.