When chlorine water is exposed to sunlight,$O_2$ is liberated. Hence

Which of the following is used as a moderator in a nuclear reactor?

Observe the following statements:
$1.$ Heavy water is harmful for the growth of animals.
$2.$ Heavy water reacts with $Al_4C_3$ and forms $\text{deuterated acetylene}$.
$3.$ $BaCl_2 \cdot 2D_2O$ is an example of $\text{interstitial deuterate}$.
The correct statements are:

What is meant by 'demineralised' water and how can it be obtained?

The metal salts formed during the softening of hard water using $Clark's$ method are:

Explain the structure of water.