Question

Although $D_{2}O$ resembles $H_{2}O$ chemically yet it is a toxic substance. Explain.

Answer 1

Deuterium ($^2H$) is an isotope of hydrogen ($^1H$) and though $D_2O$ is a stable isotope of $H_2O$ it is considered toxic for living beings.

If we consider mere physical properties, they are different in some ways from actual water.

The viscosity and density are both higher than normal water even the pH is not same. When organism consume $D_2O$, the difference in structure of $H_2O$ causes effects like the solvent isotope effect and kinetic isotope effect that affects the growth of cell and impairment in cell division.

Answer 2

Above explaination is the best....☺✌☺