Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
Manipal MET2021Chemistryp Block Elements (Group 15, 16, 17 & 18)

Pure cold conc. HNO ₃ makes iron passive, as the surface is covered with protective layer of

Options

  1. AFe ₂ O ₃
  2. BFeO
  3. CFe ₃ O ₄
  4. DFe ( NO ₃ )₃

Correct answer

C. Fe ₃ O ₄

Step-by-step solution

Cold conc. HNO ₃ makes it passive in which state it fails to exhibit the properties of normal iron. Passivity is said to be due to the deposit of a thin layer of iron oxide ( Fe ₃ O ₄ ) on the surface.

Practice p Block Elements (Group 15, 16, 17 & 18) on Quantrex Academy →

More from p Block Elements (Group 15, 16, 17 & 18)

Which among the following is NOT in accordance with the property stated against it? 2026Complete hydrolysis of Xenon hexafluoride gives HF along with compound X. The hybridisation in X is 2025Orthophosphorus acid on disproportionation gives PH ₃ and another oxoacid of phosphorus ' X '. The basicity of X is 2025Observe the following P ₄+ SOCl ₂ Products P ₄+ SO ₂ Cl ₂ Products In both the reactions, a common product ' x ' is obtained. The number of lone pair of elecrons on the central ato 2025The number of P = O , P - P bonds present in oxoacid of phosphorus, prepared by treating red P ₄ with alkali are respectively 2025Which of the following is not correct? 2025Nature of two oxides of nitrogen X and Y formed in the reaction of sodium nitrite with hydrochloric acid is 2025Which of the following is not correct ? 2025 Full p Block Elements (Group 15, 16, 17 & 18) list All Manipal MET PYQs