Extraction of Metals - Result Question 41
####41. Iron is rendered passive by treatment with concentrated
(a) $H _2 SO _4$
(b) $H _3 PO _4$
(c) $HCl$
(d) $HNO _3$
(1982)
Objective Questions II
(One or more than one correct option)
Show Answer
Solution:
- Iron is rendered passive by concentrated $HNO _3$ due to formation of a thick protective layer of $Fe _3 O _4$.
