Question

Gas liberated when manganese dioxide reacts with hydrochloric acid

• A. Oxygen
• B. Hydrogen
• C. Chlorine
• D. Hydrogen chloride

Answer 1

The correct option is C

Chlorine

The explanation for correct option:

(C) Chlorine:

The reaction of manganese dioxide and hydrochloric acid gives:

• When manganese $\left(IV\right)$ oxide is treated with concentrated hydrochloric acid, chlorine gas is liberated.
• Chlorine gas is greenish yellow is colour and it is of suffocating pungent odour.
• When it is treated with moist blue litmus, it turns the litmus red, then decolorizes it due to bleaching action.
• It also turns start iodine paper to blue-black colour. As reaction of chlorine gas with potassium iodide gives iodine gas, which on reaction with starch turns blue-black in colour.
• Therefore, option (c) is correct.

$$\begin{gathered} Mn{O}_2+4HCl\stackrel{\Delta }{\to }MnC{l}_2+C{l}_2+2H_{2}O \\ ManganeseHydrogenManganese\left(II\right)Chlorine \\ dioxidechloridechloride \end{gathered}$$

The explanation for incorrect option:

(A) Oxygen:
In the reaction of manganese dioxide and hydrochloric acid, oxygen is not liberated.

(B) Hydrogen:
Reaction of manganese dioxide and hydrochloric acid gives chlorine gas and not hydrogen gas.

(D) Hydrogen chloride:

Hydrogen chloride gas is not formed as a product in this reaction.