​What happens when concentrated hydrochloric acid is added to manganese dioxide?​

Correct option is C

The correct answer is (c) Manganese dioxide is reduced to manganese (II) chloride

• When concentrated hydrochloric acid is added to manganese dioxide, chlorine gas is produced, along with manganese(II) chloride and water.
• ​Manganese dioxide is a strong oxidizing agent that oxidizes hydrochloric acid to chlorine gas​

The chlorine gas produced has the following properties:

• Greenish yellow in color
• Suffocating, pungent odor
• Turns moist blue litmus red, then decolorizes it
• Turns starch iodine paper blue-black