The geometry of paramagnetic nickel complex [NiCl₄]²⁻ is:
d⸠paramagnetic prefers tetrahedral.
tetrahedral
octahedral
square planar
distorted octahedral
Ni²⁺ in [NiCl₄]²⁻ is 3d⁸ and paramagnetic, hence adopts tetrahedral geometry. Square planar is typical for diamagnetic d⁸ complexes.
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