From the following statements regarding H₂O₂, choose the incorrect statement:

• It can act only as an oxidising agent

• It decomposed on exposure to light

• It has to be stored in plastic or wax lined glass bottles in dark

• It has to be kept away from dust

In context with the industrial preparation of hydrogen from water gas (CO + H₂), which of the following is the correct statement?

• CO and H2 are fractionally separated using differences in their densities

• CO is removed by absorption in aqueous Cu2Cl2 solution

• H₂ is removed through occlusion with Pd

• CO is oxidised to CO₂ with steam in the presence of a catalyst followed by absorption of CO₂ in alkali

D.

CO is oxidised to CO₂ with steam in the presence of a catalyst followed by absorption of CO₂ in alkali

In which of the following reactions H₂O₂ acts as a reducing agent?
I. H₂O₂ + 2H⁺ + 2e^- →2H₂O
II. H₂O₂ - 2e^- →O₂ + 2H⁺
III. H₂O₂ +2e^-→ 2OH^-
IV. H₂O₂+ 2OH^- -2e^- →O₂ + 2H₂O

• I and II

• III and IV

• I and III

• II and IV

The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm, respectively. This water is unsuitable for drinking due to the high concentration of:

• Lead

• Nitrate

• Iron

• Fluoride

Very pure hydrogen (99.9%) can be made by which of the following processes?

• Reaction of methane with steam

• Mixing natural hydrocarbons of high molecular weight

• Electrolysis of water

• Reaction of salt like hydrides with water