Of the following complex ions, which is diamagnetic in nature?

1.  ${\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]}^{2-}$

2.  ${\left[{\mathrm{CuCl}}_4\right]}^{2-}$

3.  ${\left[{\mathrm{CoF}}_6\right]}^{3-}$

4.  ${\left[{\mathrm{NiCl}}_4\right]}^{2-}$

Which of the following statements about the order of reaction is incorrect?

The correct order of increasing bond length of  C-H, C-O, C-C and C=C is:

1.  $\mathrm{C}-\mathrm{C}<\mathrm{C}=\mathrm{C}<\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{H}$

2.  $\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{H}<\mathrm{C}-\mathrm{C}<\mathrm{C}=\mathrm{C}$

3.  $\mathrm{C}-\mathrm{H}<\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{C}<\mathrm{C}=\mathrm{C}$

4.  $\mathrm{C}-\mathrm{H}<\mathrm{C}=\mathrm{C}<\mathrm{C}-\mathrm{O}<\mathrm{C}-\mathrm{C}$

Which of the following is least likely to act as a Lewis base?

The polymer that can be classified as polyster polymer is:
1. Bakelite
2. Melamine
3. Nylon-66
4. Terylene

A buffer solution is prepared in which the concentration of NH₃ is 0.30 M and the concentration of  $N{H}_4^{+\hspace{0.17em}}$ is 0.20 M. If the equilibrium constant, K_b for NH₃ equals 1.8×10^–5, then what is the pH of this solution? 
(log 1.8 = 0.25; log 0.67 = –0.176)

1.  9.43
2.  11.72
3.  8.73
4.  9.08

What is the standard cell potential when the Sn⁴⁺/Sn²⁺ (E° = +0.15 V) and Cr³⁺/Cr (E° = −0.74 V) half-cells are connected under standard conditions?

1. +0.89 V

2. +0.18 V

3. +1.83 V

4. +1.199 V

The product 'D' in the below-mentioned reaction will be:

1.		2.
3.		4.