क्लोरीन (en. Chlorine)

Residual chlorine or chloramines may also be capable of chlorinating organic material in the natural aquatic environment.

The US has said there were indications that a toxic chemical, probably chlorine, was used in Syria this month and it is trying to establish whether the Assad regime was responsible for it.

There was less quantity of chlorine in the water.

UK fears chlorine-based chemical terror attack.

And chlorine is the best example because residual chlorine can be measured easily and quickly in the field.

The question before the court was whether the chlorine plant should be allowed to re-start operations.

Chlorine's atomic number is 17.