From the following statements, choose the incorrect statement regarding $$H_2O_2$$.

We are given four statements about hydrogen peroxide (H₂O₂) and need to identify the incorrect one. Let's evaluate each option step by step.

Starting with Option A: "It has to be kept away from dust." Hydrogen peroxide decomposes readily in the presence of catalysts like dust particles, which accelerate the breakdown into water and oxygen gas. The reaction is: $$2H_2O_2 \rightarrow 2H_2O + O_2$$. Therefore, keeping H₂O₂ away from dust is a necessary precaution, making this statement correct.

Now Option B: "It can act only as an oxidising agent." Hydrogen peroxide can act as both an oxidising agent and a reducing agent. As an oxidising agent, it accepts electrons (e.g., oxidizing I⁻ to I₂ in acidic medium): $$H_2O_2 + 2H^+ + 2e^- \rightarrow 2H_2O$$. As a reducing agent, it donates electrons (e.g., reducing acidified KMnO₄): $$H_2O_2 \rightarrow O_2 + 2H^+ + 2e^-$$. Since H₂O₂ exhibits dual behavior, the claim that it acts "only" as an oxidising agent is false.

Option C: "It decomposes on exposure to light." Light catalyzes the decomposition of H₂O₂. The reaction is: $$2H_2O_2 \rightarrow 2H_2O + O_2$$. Thus, storing H₂O₂ in dark bottles is standard practice, confirming this statement as correct.

Option D: "It has to be stored in plastic or wax-lined glass bottles in the dark." Alkaline glass can catalyze decomposition, so plastic or wax-lined glass prevents contact with reactive surfaces. Storing in the dark avoids photodecomposition, as explained in Option C. Hence, this storage method is valid, making the statement correct.

Only Option B is incorrect because H₂O₂ can act as both an oxidising and a reducing agent. Hence, the correct answer is Option B.