Aqueous solutions of zinc sulphate and iron sulphate were taken in test tubes I and II by four students A, B, C, and D. Metal pieces of iron and zinc were dropped in the two solutions, and observations made after several hours were recorded in the form of a table as given below:

Student SolutionMetalSolutionColour change Deposit/coating of solutionDeposit/coating obtained
AFeZnSO4Turned greenSilvery grey deposit
ZnFeSO4No changeNo change
BFeZnSO4No changeBlack deposit
ZnFeSO4Colour fadedGrey coating
CFeZnSO4No changeNo change
ZnFeSO4Turned colourlessBlack deposit
DFeZnSO4No changeGrey deposit
ZnZnSO4No changeBlack deposit

Which student has given the correct report?
  1. A
  2. D
  3. A
  4. C

AcademicChemistryNCERTClass 10

Correct Answer: (d) C

Explanation: Fe is less reactive than zinc.

$Fe(s) + ZnSO_4(aq) \rightarrow no \ reaction$

Zn is more reactive than Fe, so it displaces iron as follows:

$Zn(s) + FeSO_4(aq) (green) \rightarrow ZnSO_4(aq) (colourless) + Fe(s) (black \ deposit)$

Updated on 10-Oct-2022 12:47:03