MCQ
Pure conc. $HN{O_3}$makes iron passive as the surface is covered with protective layer of
- A$F{e_2}{O_3}$
- B$FeO$
- ✓$F{e_3}{O_4}$
- D$Fe{(N{O_3})_3}$
✓
Answer
Correct option: C.
$F{e_3}{O_4}$
c
(c)The passivity of iron is due to the formation of a thin insoluble and invisible iron film on surface which prevents its further reactions. The film is due to the formation of $F{e_3}{O_4}$.
(c)The passivity of iron is due to the formation of a thin insoluble and invisible iron film on surface which prevents its further reactions. The film is due to the formation of $F{e_3}{O_4}$.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
When $AlCl_3·6H_2O$ is strongly heated, then it forms
→Which is the decreasing order of stability
→$(i)$ $C{H_3} - \mathop C\limits^ + H - C{H_3}$
$(ii)$ $C{H_3} - \mathop C\limits^ + H - O - C{H_3}$
$(iii)$ $C{H_3} - \mathop C\limits^ + H - CO - C{H_3}$
Simplified absorption spectra of three complexes $((i),$$( ii)$ and $( iii ))$ of $M ^{ n +}$ ion are provided below; their $\lambda_{\max }$ values are marked as $A, B$ and $C$ respectively. The correct match between the complexes and their $\lambda_{\max }$ values is
→$(i)$ $\left[ M ( NCS )_{6}\right]^{(-6+ n )}$
$(ii)$ $\left[ MF _{6}\right]^{(-6+ n )}$
$(iii)$ $\left[ M \left( NH _{3}\right)_{6}\right]^{ n ^{+}}$
The electronic configuration with the highest ionization enthalpy is
According to $MO$ theory, number of species/ions from the following having identical bond order is $.........$
→$CN ^{-}, NO ^{+}, O _{2}, O _{2}^{+}, O _{2}^{2+}$
Which of the following has minimum melting point
Which pair represents chain isomer
The noble gas was first time discovered by
Ionic product of water increases, if
A nauseating smell in the carbylamine test for primary amines is due to the formation of