Chemistry

Coordination Chemistry

319 Questions

Coordination chemistry focuses on coordination compounds, their structures, and their magnetic properties. The questions cover primary and secondary valencies, ligand types, and geometries of complexes. This topic is heavily tested in chemistry competitive exams and requires a good grasp of molecular structures.

primary and secondary valencycomplex geometriesligand field theorymagnetic properties of complexesisomerism in complexes

Coordination Chemistry Questions

Multiple choice

Which of the following pair of coordination compound has same magnetic moments?

  1. [Mn(CN)2(NH3)4], [Fe(CN)3(H2O)3]

  2. K2[Co(Cl)2(OH)2(NH3)2], [Zn(H2O)2(Py)2(NO2)2]

  3. [V(C2H5O)2(en)2], [Ni(CN)2(NH3)4]

  4. [Fe(CN)3(NH3)3] [Cr(CO)3(Cl)3]

  5. Both 1 and 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct, because the central metal ions of both the compounds have same (five) unpaired electron in their d-orbitals, on basis of this fact both compounds show the same magnetic moment.

Multiple choice

Which pair of 'coordination complex: IUPAC name’ is not correctly matched?

  1. [Co(NH3)5ONO]2+: pentaamminenitritocobalt(III) ion

  2. K3[Co(C2O4)3]: potassium trioxalatocobaltate(II)

  3. [Cr(NH3)6][IrCl6]: hexaamminechromium(III) hexachloroiridate(III)

  4. [Cr(H2O)5Br]SO4: pentaaquabromochromium(III) sulphate

  5. [Cu(H2O)4]SO4: tetraaquacopper(II) sulphate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The correct IUPAC name of K3[Co(C2O4)3] complex is potassium trioxalatocobaltate(III).

Multiple choice

Which pair represents ionization isomers only?

  1. [Pt(NH3)4] [PtCl4] and [PtCl(NH3)3] [PtCl3(NH3)]

  2. [Co(NH3)6] [Cr(CN)6] and [Cr(NH3)6] [Co(CN)6]

  3. [Cr(H2O)6]Cl3 and [Cr(H2O)5Cl]Cl2.H2O

  4. [Co(NO2)(NH3)5]Cl2 and [Co(ONO)(NH3)5]Cl2

  5. [CoCl2(NH3)4]NO2 and [Co(Cl)(NO2)(NH3)4]Cl
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

[CoCl2(NH3)4]NO2 and [Co(Cl)(NO2)(NH3)4]Cl both complexes are ionization isomers.

Multiple choice action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

When aluminium hydroxide is reacted with excess sodium hydroxide, the soluble amphoteric compound is formed. Mark the correct formula. 

  1. $\displaystyle { \left[ { Al\left( OH \right) } _{ 4 } \right] }^{ - }$
  2. $\displaystyle { \left[ { Al\left( OH \right) } _{ 5 } \right] }^{ 2- }$
  3. $\displaystyle { \left[ { Al\left( OH \right) } _{ 6 } \right] }^{ 3- }$
  4. $\displaystyle { \left[ { Al\left( OH \right) } _{ 7 } \right] }^{ 4- }$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$Al(OH) _3 + NaOH \rightarrow Na^+ [Al(OH) _4]^-$

 Aluminium hydroxide when reacted with excess sodium hydroxide, the soluble amphoteric compound  formed is sodium tetra hydroxoaluminate (III).

Multiple choice action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

When aluminium hydroxide is reacted with excess ammonium hydroxide, the insoluble compound is formed. Mark the correct formula.

  1. $\displaystyle { \left[ { Al\left( OH \right) } _{ 4 } \right] }^{ 1- }$
  2. $\displaystyle { \left[ { Al\left( OH \right) } _{ 5 } \right] }^{ 2- }$
  3. $\displaystyle { \left[ { Al\left( OH \right) } _{ 6 } \right] }^{ 3- }$
  4. $\displaystyle { \left[ { Al\left( OH \right) } _{ 7 } \right] }^{ 4- }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Aluminium hydroxide reacts with excess hydroxide ions to form the soluble tetrahydroxoaluminate complex, [Al(OH)4]-. However, in some contexts, the hexahydroxoaluminate complex [Al(OH)6]3- is also discussed in coordination chemistry.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) uses of alkali and alkaline earth metals uses of s block elements group 1 elements: alkali metals

$Sr^{2+}$ forms a very unstable complex with $NO _{3-}$. A solution that was $0.001 M - Sr(ClO _{4}) _{2}$ and $0.05 M - KNO _{3}$ was found to have only $75$% of its strontium in the uncomplexed $Sr^{2+}$ form, the balance being $Sr(NO _{3})^{+}$. What is $K _{f}$ for complexation?

  1. $6.67$
  2. $0.15$
  3. $60$
  4. $26.67$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Given 25% complexation (0.00025 M) and 75% free Sr2+ (0.00075 M), with [NO3-] = 0.05 M, Kf = [Sr(NO3)+] / ([Sr2+][NO3-]) = 0.00025 / (0.00075 * 0.05) = 0.00025 / 0.0000375 = 6.666...

Multiple choice limestone uses of group 2 compounds group 2 industrial inorganic chemistry chemistry

Nuclear attraction is often the deciding control factor for the association of natural molecules to
a given metal ion. Which one of the following represents the correct order of stability of the ions?
$[Be(H _2O) _4]^{2+} , [Mg(H _2O) _4]^{2+} , Ca(H _2O) _4]^{2+} and          Sr(H _2O)^4]^{2+}$

  1. $[Be(H _2O) _4]^{2+} > Sr(H _2O) _4]^{2+}] > [Mg(H _2O) _4]^{2+} > [Ca(H _2O)^4]^{2+}$
  2. $[Ca(H _2O) _4]^{2+} > [Mg(H _2O) _4]^{2+} > [Be(H _2O) _4]^{2+} > Sr(H _2O) _4]^{2+}$
  3. $[Sr(H _2O) _4]^{2+} > [Ca(H _2O) _4]^{2+} > [Mg(H _2O) _4]^{2+} > [Be(H _2O) _4]^{2+}$
  4. $[Be(H _2O) _4]^{2+} > [Mg(H _2O) _4]^2 > [Ca(H _2O) _4]^{2+} > Sr(H _2O) _4]^{2+}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The degree of hydration and the amount of hydration energy decreases as the size of the ion increases from   Be^{2+} to Sr^{2+}. 

                      $Be^{2+}       <      Mg^{2+}     <    Ca^{2+}    <     Sr^{2+}$

Hydration   -2494        - 1921          -1577         -1443 

Ergy (kJ moI$^{-1})$ 

Thus, stability of hydrated ion is 

$[Be(H _2O) _4]^{2+} >[Mg(H _2O _4]^{2+} > [Ca(H _2O) _4]^{2+} > [Sr(H _2O) _4]^{2+}$
Multiple choice pseudo first order reaction order of reactions chemical kinetics electrochemistry and chemical kinetics chemistry

Nitrosy ligand binds to d-metal atoms in liner and bent fashion and behaves, respectively, as _______________.

  1. $NO^{+}$ and $NO^{+}$
  2. $NO^{+}$ and $NO^{-}$
  3. $NO^{-}$ and $NO^{-}$
  4. $NO^{-}$ and $NO^{+}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Linear nitrosyl (NO) ligands act as 3-electron donors (NO+), while bent nitrosyl ligands act as 1-electron donors (NO-).

Multiple choice chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

$Cr - C$ bond in the compound $[Cr(CO) _6]$ shows $\pi$ - character due to :

  1. covalent bonding

  2. coordinate bonding

  3. synergic bonding

  4. ionic bonding
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  1. Synergic bonding is the description of the bonding of $\pi$ - configuration ligands to the transition metal which involves donation of electrons through back bonding.
    2. Mainly carbonyl ligands in complex compounds involves in this type of bonding.
Multiple choice chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

Consider the following complexes $[V(CO) _6]^-,[Cr(CO) _6]$ and $[Mn(CO) _6]^+$. Then incorrect statement(s) about metal carbonyls is /are

  1. 'C-O' bond is strongest in the cation and weakest in the anion

  2. 'C-O' bond order is less in the cation than in anion

  3. 'C-O' bond longer in the cation than in anion or neutral carbonyl

  4. 'M-C' bond order is higher in the carbon than in anionic or neutral carbonyl.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In metal carbonyls, as the negative charge on the complex increases, back-bonding from metal to CO increases, strengthening the M-C bond and weakening the C-O bond. Thus, the C-O bond is weakest in the anion and strongest in the cation.

Multiple choice chemistry coordination chemistry bonding in metal carbonyls metal carbonyls coordination compounds

If CO ligands are substituted by NO in respective neutral carbonyl compounds then which of the following will not be correct formula?

  1. $Cr(CO) _3(NO) _2$
  2. $Fe(CO) _2(NO) _2$
  3. $Cr(NO) _4$
  4. $Ni(CO) _2(NO) _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Using the 18-electron rule, Cr(CO)6 has 18 electrons. Substituting CO (2e) with NO (3e) changes the count. Cr(CO)3(NO)2 would have 6 + 6 + 6 = 18 electrons. However, Cr(NO)4 is not a stable neutral carbonyl-like complex following this substitution pattern.