Out of Fe²⁺, Co²⁺, Cr³⁺, Ni²⁺, the one which shows the lowest magnetic moment is:
[Atomic number: Fe = 26, Co = 27, Ni = 28, Cr = 24]
Magnetic moment ∠unpaired electrons.
Fe²⁺
Co²⁺
Cr³⁺
Ni²⁺
Ni²⁺ has 3d⁸ configuration with 2 unpaired electrons, giving the lowest magnetic moment compared to others.
Given below are two statements regarding conformations of n-butane. Choose the correct option. 
Consider a weak base \(B\) of \(pK_b = 5.699\). \(x\) mL of \(0.02\) M HCl and \(y\) mL of \(0.02\) M weak base \(B\) are mixed to make \(100\) mL of a buffer of pH \(=9\) at \(25^\circ\text{C}\). The values of \(x\) and \(y\) respectively are

