Which of the following pairs of ions have same paramagnetic moment?

The paramagnetic moment of an ion is determined by the number of unpaired electrons in the ion. The more unpaired electrons, the greater the paramagnetic moment.

Cu²⁺ and Ti³⁺ both have 1 unpaired electron in the d orbital. This means that they have the same paramagnetic moment.

The other pairs of ions in the question, Ti⁴⁺, Ni²⁺, and Mn²⁺, all have different numbers of unpaired electrons. This means that they have different paramagnetic moments.

Here is a table of the electronic configurations and paramagnetic moments of the ions in question:

Ion	Electronic Configuration	Paramagnetic Moment
Cu2+	3d9	1 unpaired electron
Ti3+	3d1	1 unpaired electron
Ti4+	3d0	0 unpaired electrons
Ni2+	3d8	2 unpaired electrons
Mn2+	3d5	5 unpaired electrons

As you can see, Cu²⁺ and Ti³⁺ are the only ions with 1 unpaired electron. This means that they have the same paramagnetic moment.

So the answer is (1), Cu²⁺, Ti³⁺.