Exams › JEE Main › Chemistry

Zinc liberates hydrogen gas with dilute H2SO4 and HCl, but not with HNO3, because:

1. Zn behaves as an oxidising agent on reacting with HNO3
2. HNO3 is a weaker acid than H2SO4 and HCl
3. In the electrochemical series, Zn is placed above hydrogen
4. NO3− gets reduced in preference to hydronium ion

Correct answer: NO3− gets reduced in preference to hydronium ion

Solution

With dilute HNO3 the nitrate ion is reduced (to NO/NO2) in preference to H+, so H2 is not liberated. The stored 'weaker acid' reason is incorrect; the correct reason is option 3.

Related JEE Main Chemistry questions

• What volume of 20-volume hydrogen peroxide is needed to produce 5 L of oxygen gas at STP?
• Which one of the following reactions shows sulfuric acid acting as an oxidizing agent?
• Which of the following statements about redox behavior are true? (i) A metal M whose standard reduction potential for the half-reaction Mⁿ⁺ + ne⁻ ⇌ M is highly negative acts as a strong reducing agent. (ii) The oxidizing strength of the halogens falls in the order chlorine to iodine. (iii) The reducing strength of hydrogen halides rises from hydrogen chloride to hydrogen iodide.
• For the balanced redox equation X MnO4⁻ + Y C2O4²⁻ + Z H⁺ → X Mn²⁺ + 2Y CO2 + Z/2 H2O, what are the values of X, Y, and Z, respectively?
• Balance the redox equation below and identify the coefficients X, Y and Z in order: XNa2HAsO3 + YNaBrO3 + ZHCl → NaBr + H3AsO4 + NaCl
• Arrange the following sulphur-containing anions in order of increasing oxidation state of sulphur: SO3²⁻, S2O4²⁻ and S2O6²⁻.

⚔️ Practice JEE Main Chemistry free + battle 1v1 →