The pair of which salts are expected to have the same colour in their freshly prepared aqueous solutions.
Answer & explanation
Correct answer: option 1
The correct answer is option 1. \(VOCl_2, CuCl_2\).
The color of a transition metal salt in aqueous solution is determined by the number of unpaired electrons in the metal ion. Both \(VOCl_2\) and \(CuCl_2\) contain a \(Cu^{2+}\) ion, which has one unpaired electron. This means that the two salts will have the same color in their freshly prepared aqueous solutions.
The other options are incorrect.
Option (2) \(CuCl_2\) and \(FeCl_2\) , is incorrect because \(FeCl_2\) has two unpaired electrons, while \(CuCl_2\) has only one unpaired electron.
Option (3) \(FeCl_2\) and \(VOCl_2\), is incorrect because \(FeCl_2\) has two unpaired electrons, while \(VOCl_2\) has only one unpaired electron.
Option (4), \(MnCl_2\) and \(FeCl_2\), is incorrect because \(MnCl_2\) has five unpaired electrons, while \(FeCl_2\) has only two unpaired electrons.