Which from following cations in their respective oxidation states develops colourless aqueous solution?

Calculate osmotic pressure of $$0.2 \mathrm{~M}$$ aqueous $$\mathrm{KCl}$$ solution at $$0^{\circ} \mathrm{C}$$ if van't Hoff factor for $$\mathrm{KCl}$$ is 1.83. $$\left[\mathrm{R}=0.082 \mathrm{~dm}^3 \mathrm{~atm} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right]$$

If $$\mathrm{f}(x)=3^x ; \mathrm{g}(x)=4^x$$, then $$\frac{\mathrm{f}^{\prime}(0)-\mathrm{g}^{\prime}(0)}{1+\mathrm{f}^{\prime}(0) \mathrm{g}^{\prime}(0)}$$ is

If $$x=\frac{5}{1-2 \mathrm{i}}, \mathrm{i}=\sqrt{-1}$$, then the value of $$x^3+x^2-x+22$$ is