______ gas is used for the manufacturing of bleaching powder.

Correct option is D

Chlorine gas is used to manufacture bleaching powder, which is a white solid that is used as a disinfectant and a bleaching agent. Bleaching powder is made by passing chlorine gas over dry slaked lime (calcium hydroxide). The reaction produces calcium hypochlorite, which is the active ingredient in bleaching powder.
 Chlorine is a yellow-green gas at room temperature. Chlorine has a pungent, irritating odor similar to bleach that is detectable at low concentrations.
 The density of chlorine gas is approximately 2.5 times greater than air, which will cause it to initially remain near the ground in areas with little air movement.