Exams › JEE Advanced › Chemistry

In how many of the following processes is H2 gas released as a product? (i) Na + H2O --> (ii) KH + H2O --> (iii) CO + H2 (steam, Fe2O3/Cr2O3 catalyst) --> (iv) Electrolysis of fused (molten) NaH (v) Electrolysis of acidic water

1. 1
2. 2
3. 3
4. 4

Correct answer: 4

Solution

Processes (i), (ii), (iv), and (v) all release H2. In (iii), CO is reduced by H2 (water-gas shift or CO + H2 gives syngas further reactions); the reaction CO + H2O gives CO2 + H2 (water-gas shift, so H2 IS produced). But CO + H2 with steam/catalyst — this produces more H2 via water-gas shift. Let us re-examine (iii): if the starting material is CO + H2 being fed with steam over Fe2O3/Cr2O3, this is the water-gas shift reaction (CO + H2O -> CO2 + H2), which PRODUCES H2. So all 5 processes produce H2? But the answer options max is 4.

Related JEE Advanced Chemistry questions

• In its interactions with potassium periodate (KIO4) and hydroxylamine (NH2OH), hydrogen peroxide functions respectively as a
• Among the two isomers of hydroxybenzoic acid, the ortho isomer is a stronger acid compared to its para counterpart. Which of the following best explains this observation?
• In which of the following reactions is hydrogen gas produced?
• How many of the following compounds are classified as saline (ionic) hydrides? NaH, MgH2, CaH2, VH0.56, Fe3H, NH3
• The wavelength of the series limit (longest wavelength limit, i.e., the convergence limit) of the Lyman series of hydrogen is x angstrom. Calculate the wave number (in angstrom⁻¹) of the third line of the Balmer series of He+ ion.
• Match the species in Column I with their correct properties or uses in Column II. Column I: A. H (atomic hydrogen) B. H2 (dihydrogen) C. H2O (water) D. H2O2 (hydrogen peroxide) Column II: (i) Known commercially as perhydrol (ii) Can be reduced by NaH to give dihydrogen (iii) Used in the catalytic hydrogenation of alkenes (iv) Used in cutting and welding of metals

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →