Chapter 19

The d-orbitals participating in hybridization of central metal atom may be from the outermost shell or the penultimate shell. This depends on the nature of metal and the nature of ligand. The complexes involving the inner d level (inner orbital complexes) result when the ligand is a powerful or strong ligand resulting in diamagnetic or low spin complexes. A weak ligand usually results in the formation of outer orbital complex or high spin complex. The number of unpaired electrons present in \(\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}\) and \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{2+}\) are, respectively (a) 0,0 (b) 0,4 (c) 1,2 (d) 2,4

Match the following $$ \begin{array}{ll} \hline \text { List-I } & \text { List-II } \\ \hline \text { (a) Coloured ion } & \text { (p) } \mathrm{Cu}^{+} \\ \text {(b) } \mu=1.73 \mathrm{~B} \cdot \mathrm{M} & \text { (q) } \mathrm{Cu}^{2+} \\ \text { (c) } \mathrm{d}^{10} \text { configuration } & \text { (r) } \mathrm{Fe}^{2+} \\ \text { (d) More than } 3 \text { un-paired } & \text { (s) } \mathrm{Mn}^{2+} \\\ \text { electrons } & \end{array} $$

Match the following $$ \begin{array}{ll} \hline \text { List-I } & \text { List-II } \\ \hline \text { (a) } \mathrm{Ti}^{3+} & \text { (p) Paramagnetic } \\ \text { (b) } \mathrm{Cu}^{2+} & \text { (q) Coloured } \\ \text { (c) } \mathrm{Co}^{2+} & \text { (r) One un-paired electron } \\ \text { (d) } \mathrm{Zn}^{2+} & \text { (s) Diamagnetic } \end{array} $$

Match the following $$ \begin{array}{ll} \hline \text { Column-I } & \text { Column-II } \\ \hline \text { (a) } \mathrm{Ce}^{4+} & \text { (p) Oxidizing agent in volu- } \\\ \text { metric analysis } \\ \text { (b) } \mathrm{Nd}^{3+} & \text { (q) Misch metal } \\ \text { (c) } \mathrm{La}^{3+} & \text { (r) Colourless salts } \\ \text { (d) } \mathrm{Pr}^{3+} & \text { (s) Coloured glases for gog- } \\ \text { gles. } \end{array} $$

When the sample of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are Cathode Anode \(\begin{array}{ll}\text { (a) pure zinc } & \text { pure copper }\end{array}\) (b) pure copper impure sample (c) impure zinc impure sample (d) impure sample pure copper

Number of electrons transferred in each case when \(\mathrm{KMnO}_{4}\) acts as an oxidizing agent to give \(\mathrm{MnO}_{2}\), \(\mathrm{Mn}^{2+}, \mathrm{Mn}(\mathrm{OH})_{2}\) and \(\mathrm{MnO}_{4}^{2-}\) are respectively (a) \(1,3,4\) and 5 (b) \(4,3,1\) and 5 (c) \(5,4,3\) and 1 (d) \(3,5,4\) and 1

The most stable ion is (a) \(\left[\mathrm{Fe}(\mathrm{OH})_{5}\right]^{3-}\) (b) \(\left[\mathrm{FeCl}_{6}\right]^{3-}\) (c) \(\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}\) (d) \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}\)

Most common oxidation states of Ce are (a) \(+3,+4\) (b) \(+2,+3\) (c) \(+2,+4\) (d) \(+3,+5\)

The atomic number of \(\mathrm{V}, \mathrm{Cr}, \mathrm{Mn}\) and \(\mathrm{Fe}\) are respectively \(23,24,25\) and 26 . which one of these may be expected to have the highest second ionization enthalpy? (a) \(\mathrm{Mn}\) (b) \(\mathrm{Fe}\) (c) \(\mathrm{Cr}\) (d) \(\mathrm{V}\)

What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid? (a) \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}\) and \(\mathrm{H}_{2} \mathrm{O}\) are formed (b) \(\mathrm{Cr}^{3+}\) and \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}\) are formed (c) \(\mathrm{CrO}_{4}^{2-}\) is oxidized to \(+7\) state to \(\mathrm{Cr}\) (d) \(\mathrm{CrO}_{4}^{2-}\) is reduced to \(+3\) state of \(\mathrm{Cr}\)

The radius of \(\mathrm{La}^{3+}\) (atomic number \(=57\) ) is \(1.06 \AA\). Which one of the following given values will be closest to the radius of \(\mathrm{Lu}^{3+}\) (atomic number \(=71\) )? (a) \(0.85 \AA\) (b) \(1.06 \AA\) (c) \(1.40 \AA\) (d) \(1.60 \AA\)

Ammonia forms the complex ion \(\left[\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4}\right]^{2+}\) with copper ions in the alkaline solutions, but not in acidic solutions. What is the reason for it? (a) in acidic solutions, hydration protects copper ions (b) the acidic solutions, protons coordinate with ammonia molecules forming \(\mathrm{NH}_{4}^{+}\)ions and \(\mathrm{NH}_{3}\) molecules are not available (c) in alkaline solutions, insoluble \(\mathrm{Cu}(\mathrm{OH})_{2}\) is precipitated which is soluble in excess of any alkali (d) copper hydroxide is an amphoteric substance

Which one of the following nitrates will leave behind a metal on strong heating? (a) ferric nitrate (b) copper nitrate (c) manganese nitrate (d) silver nitrate

For making good quality mirrors, plates of float glass are used. These are obtained by floating molten glass over a liquid metal, which does not solidify before glass. The metal used can be (a) mercury (b) tin (c) sodium (d) magnesium

Excess of \(\mathrm{KI}\) react with \(\mathrm{CuSO}_{4}\) solution and then \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) solution is added to it. Which of the following statements is incorrect for this reaction? [2004] (a) \(\mathrm{Cu}_{2} \mathrm{I}_{2}\) is formed (b) \(\mathrm{Na}_{2} \mathrm{~S}_{2} \mathrm{O}_{3}\) is oxidized (c) \(\mathrm{CuI}_{2}\) is formed (d) evolved \(\mathrm{I}_{2}\) is reduced

Which one of the following ores is best concentrated by froth floatation method (a) cassiterite (b) galena (c) malachite (d) magnetite

Aluminium chloride exists as dimer \(\mathrm{Al}_{2} \mathrm{Cl}_{6}\) in solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives (a) \(\mathrm{Al}_{2} \mathrm{O}_{3}+6 \mathrm{HCl}\) (b) \(\mathrm{Al}^{3+}+3 \mathrm{Cl}^{-}\) (c) \(\left[\mathrm{Al}(\mathrm{OH})_{6}\right]^{3-}+3 \mathrm{HCl}\) (d) \(\left[\mathrm{Al}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right]^{3+}+3 \mathrm{Cl}^{-}\)

The soldiers of Napolean's army, while on Alps during freezing winter, suffered a serious problem as regards to the tin buttons of their uniforms. White metallic tin buttons got converted to grey powder. This transformation is related to (a) an interaction with nitrogen of the air at very low temperatures (b) a change in the crystalline structure of tin (c) an interaction with water vapour contained in the humid air (d) a change in the partial pressure of oxygen in the air.

Among the properties (A) reducing (B) oxidizing (C) complexing, the set of properties shown by \(\mathrm{CN}^{-}\)ion towards metal species is (a) \(\mathrm{A}, \mathrm{B}\) (b) B, C (c) \(\mathrm{C}, \mathrm{A}\) (d) A, B, C

Cerium \((\mathrm{Z}=58)\) is an important member of the lanthanoids. Which of the following statements about cerium is incorrect? (a) the common oxidation states of cerium are \(+3\) and \(+4\) (b) the \(+3\) oxidation state of cerium is more stable than the \(+4\) oxidation state (c) the \(+4\) oxidation state of cerium is not known in solutions (d) cerium (IV) acts as an oxidizing agent

During the process of electrolytic refining of copper, some metals present as impurity, settle as anode mud. These are (a) \(\mathrm{Ag}\) and \(\mathrm{Au}\) (b) \(\mathrm{Pb}\) and \(\mathrm{Zn}\) (c) \(\mathrm{Fe}\) and \(\mathrm{Ni}\) (d) \(\mathrm{Sn}\) and \(\mathrm{Ag}\)

The oxidation state of chromium, in the final product formed by the reaction between KI and acidified potassium dichromate solution, is (a) \(+2\) (b) \(+3\) (c) \(+4\) (d) \(+6\)

The lanthanide contraction is responsible for the fact that (a) \(\mathrm{Zr}\) and \(\mathrm{Y}\) have about the same radius (b) \(\mathrm{Zr}\) and \(\mathrm{Zn}\) have the same oxidation state (c) \(\mathrm{Zr}\) and Hf have about the same atomic radius (d) \(\mathrm{Zr}\) and Nb have similar oxidation state

Which of the following factors may be regarded as the main cause of lanthanide contraction? \(\quad\) (a) poor shielding of one of \(4 \mathrm{f}\) electrons by another in the subshell (b) effective shielding of one of \(4 \mathrm{f}\) electrons by another in the subshell (c) poor shielding of 5 d-electrons by 4 f electrons (d) greater shielding of 5 d-electrons by \(4 \mathrm{f}\) electrons

The IUPAC name of the coordination compound \(\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\) is (a) potassium hexacyanoferrate (III) (b) potassium hexacyanoferrate (II) (c) tripotassium hexacyaniron (II) (d) potassium hexacyanoiron (II)

Which of the following cyano complexes would exhibit the lowest value of paramagnetic behaviour? (a) \(\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}\) (b) \([\mathrm{Co}(\mathrm{CN})]^{3-}\) (c) \([\mathrm{Mn}(\mathrm{CN})]^{3-}\) (d) \([\mathrm{Cr}(\mathrm{CN})]^{3-}\)

Lanthanoid contraction is caused due to (a) the appreciable shielding of outer electrons by \(4 \mathrm{f}\) electrons from the nuclear charge (b) the appreciable shielding on outer electrons by 5d-electrons from the nuclear charge (c) the same effective nuclear charge from \(\mathrm{Ce}\) to \(\mathrm{Lu}\) (d) the imperfect shielding of outer electrons by \(4 \mathrm{f}\) electrons from the nuclear charge

Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids, the main reason being (a) 4 f-orbitals more diffused than the 5 f-orbitals (b) Lesser energy difference between \(5 \mathrm{f}\) and \(6 \mathrm{~d}\) than between \(4 \mathrm{f}\) and \(5 \mathrm{~d}\) orbitals (c) More energy difference between \(5 \mathrm{f}\) and \(6 \mathrm{~d}\) than between \(4 \mathrm{f}\) and \(5 \mathrm{~d}\) orbitals (d) More reactive nature of the actinoids than the lanthanoids.

In context with the transition elements, which of the following statement is incorrect? (a) In the highest oxidation states, the transition metal show basic character and cationic complex. (b) In the highest oxidation states of the first five transition element (Sc to \(\mathrm{Mn}\) ), all the \(4 \mathrm{~s}\) and \(3 \mathrm{~d}\) electrons are used for bonding. (c) Once the \(\mathrm{d}^{5}\) configuration is exceeded, the tendency to involve all the \(3 \mathrm{~d}\) electrons in bonding decreases. (d) In addition to the normal oxidation states, the zero oxidation state is also shown by these elements in complex.

Knowing that the chemistry of lanthanoids (Ln) is dominated by its+3 oxidation state, which of the following statements is incorrect? (a) The ionic sizes of Ln (III) decrease in general with increasing atomic number. (b) Ln (III) compounds are generally colourless. (c) Ln (III) hydroxides are mainly basic in character. (d) Because of the large size of the Ln (III) ions the bonding in its compounds is predominantly ionic in character.

The outer electron configuration of Gd (atomic number \(=64\) ) is: (a) \(4 \mathrm{f}^{7} 5 \mathrm{~d}^{1} 6 \mathrm{~s}^{2}\) (b) \(4 \mathrm{f}^{3} 5 \mathrm{~d}^{2} 6 \mathrm{~s}^{2}\) (c) \(4 \mathrm{f}^{\mathrm{s}} 5 \mathrm{~d}^{0} 6 \mathrm{~s}^{2}\) (d) \(4 \mathrm{f}^{4} 5 \mathrm{~d}^{4} 6 \mathrm{~s}^{2}\)

In context of the lanthanoids, which of the follwoing statements is not correct? (a) Availability of \(4 \mathrm{f}\) electrons results in the formation of compound in \(+4\) state for all the members of the series. (b) There is a gradual decrease in the radii of the 15 members with increasing atomic number in the series. (c) Because of similar properties the separation of lanthanoids is not easy (d) All the members exhibit \(+3\) oxidation state. 15

The color of \(\mathrm{KMnO}_{4}\) is due to (a) \(\mathrm{M} \rightarrow \mathrm{L}\) charge transfer transition (b) \(d-d\) transition (c) \(\mathrm{L} \rightarrow \mathrm{M}\) charge transfer transition (d) \(\sigma-\sigma^{*}\) transition

Which of the following atoms has the highest first Ionization energy? (a) \(\mathrm{Na}\) (b) \(\mathrm{K}\) (c) \(\mathrm{Sc}\) (d) \(\mathrm{Rb}\)