Ans is 1 only.. 2 is excptn case.. where H2O acts as strong ligand with Co+3..so pairing occurs in 2..

**1) [Cr(H2O)6]3**

**Paramagnetism:**
Paramagnetism is the property of a substance to be attracted by an external magnetic field. It occurs due to the presence of unpaired electrons in the atoms or molecules of the substance. These unpaired electrons have magnetic moments and align themselves with the applied magnetic field, resulting in a net magnetic moment.

**Chromium (Cr):**
Chromium is a transition metal that can exhibit different oxidation states, including +3. In the case of [Cr(H2O)6]3, chromium is in the +3 oxidation state. The electronic configuration of a neutral chromium atom is [Ar] 3d54s1, and in the +3 state, it loses three electrons from the 4s and 3d orbitals, resulting in the electronic configuration [Ar] 3d3.

**[Cr(H2O)6]3:**
In [Cr(H2O)6]3, the chromium ion is surrounded by six water ligands. Each water ligand donates a lone pair of electrons to form coordinate bonds with the central chromium ion. Since chromium has three unpaired electrons in its 3d orbitals, it exhibits paramagnetic behavior.

**Explanation:**
1. The six water ligands form coordinate bonds with the central chromium ion, resulting in an octahedral coordination geometry.
2. Each water ligand donates a lone pair of electrons to form a coordinate bond with the chromium ion.
3. The three unpaired electrons in the 3d orbitals of the chromium ion align themselves with the applied magnetic field when it is present, contributing to the overall paramagnetic behavior of the complex.
4. The presence of unpaired electrons in the 3d orbitals of the chromium ion results in a net magnetic moment, making [Cr(H2O)6]3 paramagnetic.

**2) [Co(H2O)6]3**

**Cobalt (Co):**
Cobalt is another transition metal that can exhibit different oxidation states, including +3. In the case of [Co(H2O)6]3, cobalt is also in the +3 oxidation state. The electronic configuration of a neutral cobalt atom is [Ar] 3d74s2, and in the +3 state, it loses three electrons from the 4s and 3d orbitals, resulting in the electronic configuration [Ar] 3d6.

**[Co(H2O)6]3:**
In [Co(H2O)6]3, the cobalt ion is surrounded by six water ligands. Each water ligand donates a lone pair of electrons to form coordinate bonds with the central cobalt ion. Cobalt in the +3 oxidation state has three unpaired electrons in its 3d orbitals.

**Explanation:**
1. The six water ligands form coordinate bonds with the central cobalt ion, resulting in an octahedral coordination geometry.
2. Each water ligand donates a lone pair of electrons to form a coordinate bond with the cobalt ion.
3. The three unpaired electrons in the 3d orbitals of the cobalt ion have magnetic moments but do not align themselves strongly with an applied magnetic field.
4. Due to the weak alignment of the unpaired electrons, [Co(H2O)6]3 exhibits weaker param