Which statement is true about chlorine forms used in water treatment?

Which statement is true about chlorine forms used in water treatment?

• A. Chlorine can be used in gaseous form.
• B. Chlorine is only used as a liquid.
• C. Chlorine cannot be stored.
• D. Chlorine is never used for disinfection.

Answer: (A)

Chlorine can be used in gaseous form because chlorine is a gas at room temperature and pressure, and water treatment plants often inject chlorine gas into the water for disinfection. This form allows rapid dosing and effective mixing in the contact process, though it requires proper gas-handling safety and equipment. The other statements are not accurate: chlorine is not limited to a liquid form—it is also used as gas and as hypochlorite solutions or solids; chlorine can be stored (in gas cylinders or as hypochlorite products); and chlorine is widely used for disinfection, so saying it is never used for disinfection is incorrect.

Chlorine can be used in gaseous form because chlorine is a gas at room temperature and pressure, and water treatment plants often inject chlorine gas into the water for disinfection. This form allows rapid dosing and effective mixing in the contact process, though it requires proper gas-handling safety and equipment. The other statements are not accurate: chlorine is not limited to a liquid form—it is also used as gas and as hypochlorite solutions or solids; chlorine can be stored (in gas cylinders or as hypochlorite products); and chlorine is widely used for disinfection, so saying it is never used for disinfection is incorrect.