The molecule ClF3 has a T-shaped structure. Chlorine has 7 valence electrons. In ClF3, there are 3 bond pairs with fluorine and 2 lone pairs.
The most stable structure of ClF3 has the two lone pairs in the equatorial positions of a trigonal bipyramidal arrangement. Therefore, the number of lone pairs in the equatorial positions is n = 2.
Now we need to find which of the given ions have 2 unpaired electrons, matching the value of n = 2:
A. V3+: Vanadium (V) has electronic configuration [Ar] 3d3 4s2.
So V3+ has electronic configuration [Ar] 3d2.
It has 2 unpaired electrons.
B. Ti3+: Titanium (Ti) has electronic configuration [Ar] 3d2 4s2.
So Ti3+ has electronic configuration [Ar] 3d1.
It has 1 unpaired electron.
C. Cu2+: Copper (Cu) has electronic configuration [Ar] 3d10 4s1.
So Cu2+ has electronic configuration [Ar] 3d9.
It has 1 unpaired electron.
D. Ni2+: Nickel (Ni) has electronic configuration [Ar] 3d8 4s2.
So Ni2+ has electronic configuration [Ar] 3d8.
It has 2 unpaired electrons.
E. Ti2+: Titanium (Ti) has electronic configuration [Ar] 3d2 4s2.
So Ti2+ has electronic configuration [Ar] 3d2.
It has 2 unpaired electrons.
Conclusion: The ions with exactly 2 unpaired electrons are V3+, Ni2+, and Ti2+.
Final Answer: The final answer is (1) A, D and E only.
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are

Which of the following is not correct?
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,