21.

Which one of the following ions exhibits d-d transition and paramagnetism as well?

• $Cr{O}_4^{2-}$

• $C{r}_2{O}_7^{2-}$

• $Mn{O}_4^{2-}$

• $Mn{O}_4^{-}$

Iron carbonyl, Fe(CO)₅ is

• Tetranuclear

• Mononuclear

• Dinuclear

• Trinuclear

The type of isomerism shown by the complex [CoCl₂(en)₂] is

• Geometrical isomerism

• Coordination isomerism

• Linkage isomerism

• Ionization isomerism

The geometry and magnetic behaviour of the complex [Ni(CO)₄] are

• Square planar geometry and diamagnetic

• Tetrahedral geometry and diamagnetic

• Tetrahedral geometry and paramagnetic

• Square planar geometry and paramagnetic

Following solutions were prepared by mixing different volumes of NaOH and HCl of different concentrations :

$$\begin{gathered} a) 60 mL \frac{M}{10} HCl + 40 mL \frac{M}{10} NaOH \\ b) 55 mL \frac{M}{10}HCl + 45 mL \frac{M}{10} NaOH \\ c) 75 mL \frac{M}{5} HCl + 25 mL \frac{M}{5} NaOH \\ d)\hspace{0.17em}100 mL \frac{M}{10} HCl + 100 mL\frac{M}{10} NaOH \end{gathered}$$

pH of which one of them will be equal to 1?

• b

• a

• c

• d

On which of the following properties does the coagulating power of an ion depend?

• The magnitude of the charge on the ion alone

• Size of the ion alone

• The sign of the charge on the ion alone

• Both magnitude and sign of the charge on the ion

Given van der Waals constant for NH₃, H₂, O₂ and CO₂ are respectively 4.17, 0.244, 1.36 and 3.59, which one of the following gases is most easily liquefied?

• NH₃

• H₂

• CO₂

• O₂

The solubility of BaSO₄ in water is 2.42 × 10^–3 gL^–1 at 298 K. The value of its solubility product (K_sp) will be
(Given the molar mass of BaSO₄ = 233 g mol^–1)

• 1.08 x 10^-10 mol²L^-2

• 1.08 x 10^-12 mol²L^-2

• 1.08 x 10^-8 mol²L^-2

• 1.08 x 10^-14 mol²L^-2

The correct difference between first and second order reactions is that

• The rate of a first-order reaction does not depend on reactant concentrations; the rate of a second-order reaction does depend on reactant concentrations

• The half-life of a first-order reaction does not depend on [A]₀; the half-life of a second-order reaction does depend on [A]₀

• The rate of a first-order reaction does depend on reactant concentrations; the rate of a second-order reaction does not depend on reactant concentrations

• A first-order reaction can catalyzed; a second-order reaction cannot be catalyzed

When initial concentration of the reactant is doubled, the half-life period of a zero order reaction

• Is halved

• Is doubled

• Remains unchanged

• Is tripled