Chemistry
A student takes Cu, Al, Fe and Zn strips, separately in four test tubes labeled as I, II, III and IV respectively. He adds 10 ml of freshly prepared ferrous sulphate solution to each test tube and observes the colour of the metal residue in each case.
He would observe a black residue in the test tubes:
- (I) and (II)
- (I) and (III)
- (II) and (III)
- (II) and (IV)
Acids Bases Salts
ICSE Sp 2025
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Answer
(II) and (IV)
Reason — Zinc and aluminium are more reactive than iron. Therefore they will displace iron which will be seen as black residue.
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