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)
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Answer:
Correct Answer: 41. (d)
Solution:
- Iron is rendered passive by concentrated $HNO _3$ due to formation of a thick protective layer of $Fe _3 O _4$.
BETA
