Few zinc granules were added to blue-coloured copper sulphate solution. The correct observations are:
a. Zinc displaces copper from copper sulphate solution.
b. Blue-coloured solution turns to red.
c. Green patches can be seen on zinc granules.
d. Blue-coloured solution turns colourless.
1 a & d
2 a & b
3 c & d
4 c & a

Correct option is A

Correct Answer: (a)
Explanation
Zinc is more reactive than copper, so it displaces copper from copper sulphate solution.
Reaction:
Zn + CuSO₄ → ZnSO₄ + Cu
Observations:
· Zinc displaces copper from copper sulphate solution. ( Statement a is correct}
· The blue colour disappears because zinc sulphate (ZnSO₄} is colourless.
· The solution does not turn red. Instead, reddish-brown copper metal is deposited on the zinc granules.
· No green patches are formed on zinc granules.
Therefore, the correct combination is a & d.
Hence, the correct answer is Option (a}.
Additional Information
Reactivity Series (partial}:
K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au
• A more reactive metal displaces a less reactive metal from its salt solution.
• Copper deposited on zinc appears as a reddish-brown coating.
• Zinc sulphate solution is colourless, causing the blue colour of copper sulphate solution to disappear.
• This is an example of a single displacement reaction.