Here is a list of 50 Assertion and Reason questions based on Chapter 9 - Coordination Compounds from the NCERT Class 12 Chemistry book. Each question includes the answer, followed by an explanation.
Options for each question:
Assertion (A): The central metal atom in a coordination compound often exhibits a formal charge, which is the sum of the charges on the ligands.
Reason (R): The oxidation state of the metal atom in the complex is calculated by taking into account the charges on the ligands.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The central metal atom’s formal charge is determined by the oxidation state, which accounts for the charges of the ligands in the complex.
Assertion (A): Ligands can either be monodentate or polydentate depending on the number of donor atoms they have.
Reason (R): Monodentate ligands have only one donor atom, whereas polydentate ligands have multiple donor atoms.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Ligands are classified based on the number of donor atoms. Monodentate ligands bind through one donor atom, while polydentate ligands bind through multiple donor atoms.
Assertion (A): A coordination compound is formed when a metal ion binds with ligands.
Reason (R): Coordination compounds are stable because of the electrostatic attraction between the metal ion and the ligands.
Answer: B) Both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
Explanation: While the formation of coordination compounds is due to the interaction between metal ions and ligands, their stability is not solely due to electrostatic attraction; other factors like ligand field effects also contribute.
Assertion (A): The color of a coordination compound depends on the nature of the ligands attached to the metal ion.
Reason (R): The nature of the ligand affects the splitting of d-orbitals in the metal ion, which in turn affects the absorption of light.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The color of a coordination compound is determined by the electronic transitions in the d-orbitals of the metal ion, which is influenced by the ligand's nature.
Assertion (A): In coordination compounds, the oxidation state of the metal ion can be determined using the charge balance principle.
Reason (R): The charge on the complex is the sum of the oxidation state of the metal and the charges of the ligands.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The oxidation state of the metal in a coordination compound is calculated by balancing the charges on the complex with the charges of the ligands.
Assertion (A): The coordination number in a complex determines the geometry of the coordination compound.
Reason (R): The coordination number is the number of bonds formed between the central metal atom and the ligands.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The geometry of the coordination compound is directly related to the coordination number, which refers to the number of bonds formed between the metal and ligands.
Assertion (A): The coordination number of a metal in a coordination compound depends on the size of the metal ion and the ligands.
Reason (R): Larger metal ions can accommodate more ligands due to their larger size.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The coordination number is influenced by the size of the metal ion and ligands. Larger metal ions have more space to accommodate more ligands.
Assertion (A): The crystal field theory helps explain the magnetic properties of coordination compounds.
Reason (R): In crystal field theory, ligands cause the d-orbitals of the metal to split, leading to different electron configurations.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Crystal field theory explains how the splitting of metal ion d-orbitals under the influence of ligands affects the magnetic properties of coordination compounds.
Assertion (A): In an octahedral coordination complex, the ligands are positioned at the vertices of an octahedron.
Reason (R): Octahedral geometry results from six ligands being arranged symmetrically around the central metal atom.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: In octahedral coordination, the six ligands are arranged symmetrically around the metal atom, forming an octahedron.
Assertion (A): The hybridization of the central metal ion in a coordination complex is determined by the coordination number.
Reason (R): The coordination number dictates how many orbitals of the metal ion participate in bonding with ligands.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The hybridization of the central metal atom is directly related to the coordination number and the number of bonding orbitals involved in the formation of the complex.
Assertion (A): A ligand’s electron pair donor ability is important in determining the stability of a coordination complex.
Reason (R): The more electron-donating a ligand, the more stable the coordination complex becomes.
Answer: B) Both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
Explanation: While electron pair donation affects the stability, other factors like ligand field strength also play a role in determining the stability of the complex.
Assertion (A): The geometry of a coordination compound depends on the type of ligands as well as the metal ion.
Reason (R): Ligands influence the spatial arrangement of atoms in the complex, leading to different geometries such as tetrahedral, octahedral, etc.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Both the metal ion and ligands contribute to determining the geometry of the coordination compound.
Assertion (A): A chelate is a type of coordination complex where the ligand forms more than one bond with the central metal atom.
Reason (R): Chelating ligands have multiple donor atoms, allowing them to form several bonds with the metal center.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Chelating ligands are polydentate, meaning they can form multiple bonds with the metal ion, making them more stable.
Assertion (A): The splitting of d-orbitals in a metal complex affects the color of the complex.
Reason (R): The energy difference between the split d-orbitals determines the frequency of light absorbed, which influences the color.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The splitting of d-orbitals in a metal ion under the influence of ligands results in the absorption of specific wavelengths of light, giving the complex its color.
Assertion (A): Ligands can be classified as either strong field or weak field based on their ability to split the d-orbitals of a metal.
Reason (R): Strong field ligands cause a large splitting of d-orbitals, while weak field ligands cause a smaller splitting.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The classification of ligands as strong or weak field is based on their ability to cause splitting in the d-orbitals of the central metal ion.
Assertion (A): The oxidation state of the metal ion in a coordination compound is fixed and does not change with the environment.
Reason (R): The oxidation state of the metal ion is determined by the charge of the ligands and the overall charge of the complex.
Answer: B) Both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
Explanation: While the oxidation state is determined by the ligands and the charge on the complex, it can vary with the environment under certain conditions.
Assertion (A): Coordination compounds are often used in medicine due to their ability to form stable complexes.
Reason (R): Stable coordination complexes can easily bind to biomolecules, facilitating drug delivery.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The stability and specific binding properties of coordination compounds make them useful in medicine, especially in targeted drug delivery.
Assertion (A): Transition metals are commonly involved in coordination compounds due to their ability to form complexes with ligands.
Reason (R): Transition metals have vacant d-orbitals, which are available for bonding with ligands.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Transition metals can form coordination compounds because they have vacant d-orbitals, allowing ligands to donate electron pairs to form stable complexes.
Assertion (A): In a square planar complex, the central metal ion has a coordination number of four.
Reason (R): Square planar complexes have four ligands arranged symmetrically around the metal ion in a square configuration.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Square planar complexes involve four ligands arranged symmetrically around the metal ion, which leads to a coordination number of four.
Assertion (A): Coordination compounds can exist in different isomeric forms, such as geometric and optical isomers.
Reason (R): Isomerism in coordination compounds arises due to the spatial arrangement of ligands around the central metal ion.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The spatial arrangement of ligands around the metal ion leads to different isomers in coordination compounds, including geometric and optical isomers.
Assertion (A): The electronic configuration of a metal ion in a coordination compound influences the geometry of the complex.
Reason (R): The d-orbitals of the metal ion can split in different ways depending on the ligand field, which affects the geometry.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The geometry of a coordination compound depends on the arrangement of d-orbitals, which is influenced by the ligand field and the metal ion’s electronic configuration.
Assertion (A): In a coordination compound, the metal ion acts as a Lewis acid.
Reason (R): The metal ion accepts electron pairs from ligands, which are Lewis bases.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The metal ion acts as a Lewis acid because it accepts electron pairs from the ligands, which are Lewis bases.
Assertion (A): The chelate effect refers to the increased stability of coordination compounds when ligands form multiple bonds with the metal ion.
Reason (R): Chelating ligands form stable five- or six-membered rings with the central metal atom, which increases the compound's stability.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Chelating ligands, which form multiple bonds with the metal ion, increase the stability of the coordination compound due to the formation of stable ring structures.
Assertion (A): In a tetrahedral complex, the metal ion generally exhibits a coordination number of four.
Reason (R): The ligands are arranged in a tetrahedral geometry around the metal ion in such complexes.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: In a tetrahedral complex, the four ligands surround the metal ion symmetrically in a tetrahedral arrangement, leading to a coordination number of four.
Assertion (A): In some cases, the d-orbitals of a metal ion in a coordination compound may split into different energy levels.
Reason (R): The splitting of d-orbitals is caused by the interaction of the metal ion with the ligand field.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The splitting of d-orbitals in a metal ion occurs due to the ligand field effect, which causes the metal’s d-orbitals to have different energy levels, influencing the geometry and properties of the complex.
Assertion (A): The nature of the metal-ligand bonding in coordination compounds is covalent.
Reason (R): The metal ion shares electron pairs with the ligands, forming covalent bonds.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The bonding in coordination compounds is covalent because the metal ion shares electron pairs with the ligands, which are typically electron donors.
Assertion (A): A square planar geometry is commonly observed in coordination compounds of d8 metal ions.
Reason (R): Square planar geometry minimizes the repulsion between the ligands in complexes with a coordination number of four.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Square planar geometry is typically observed in complexes with d8 metal ions (like Pt(II), Ni(II)) because it minimizes repulsion between ligands when the coordination number is four.
Assertion (A): The coordination number of a metal ion in a coordination compound can never exceed 12.
Reason (R): The size of the metal ion and the ligands limits the number of ligands that can surround the metal ion.
Answer: C) Assertion is correct, but Reason is incorrect.
Explanation: The coordination number can exceed 12, but it is very rare. For example, larger metal ions (e.g., lanthanides) can have coordination numbers of 14. The reason provided is not entirely correct.
Assertion (A): A ligand can be classified as either monodentate or bidentate based on the number of donor atoms.
Reason (R): Monodentate ligands have one donor atom, while bidentate ligands have two donor atoms.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Monodentate ligands bind to the metal ion through one donor atom, while bidentate ligands can form two bonds with the metal ion due to their two donor atoms.
Assertion (A): A ligand that can form only one bond with a central metal ion is called a monodentate ligand.
Reason (R): Monodentate ligands have a single donor atom that donates an electron pair to the central metal ion.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Monodentate ligands have one donor atom, which allows them to form only one bond with the metal ion.
Assertion (A): The hybridization of the central metal ion in an octahedral complex is sp^3d^2.
Reason (R): An octahedral geometry requires six ligand bonding orbitals, which are obtained from sp^3d^2 hybridization.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: For an octahedral complex, six bonding orbitals are required, and sp^3d^2 hybridization involves the combination of one s, three p, and two d orbitals.
Assertion (A): The magnetic behavior of a coordination compound is influenced by the number of unpaired electrons in the metal ion.
Reason (R): Unpaired electrons lead to paramagnetism, while paired electrons lead to diamagnetism.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Coordination compounds with unpaired electrons are paramagnetic, while those with only paired electrons are diamagnetic. The number of unpaired electrons determines this property.
Assertion (A): The oxidation state of the metal ion in a coordination compound is always positive.
Reason (R): The metal ion typically donates electrons to form bonds with ligands, resulting in a positive charge.
Answer: B) Both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
Explanation: While the oxidation state of the metal ion is usually positive, it is not always the case (e.g., in certain complexes like [Ni(CO)₄], the metal can have a zero oxidation state).
Assertion (A): The presence of weak field ligands leads to high-spin complexes in coordination compounds.
Reason (R): Weak field ligands cause a small splitting of the d-orbitals, allowing more unpaired electrons.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Weak field ligands cause less splitting of d-orbitals, leading to high-spin complexes with more unpaired electrons.
Assertion (A): In coordination chemistry, the term "ligand" refers to an ion or molecule that donates an electron pair to the metal ion.
Reason (R): Ligands can be neutral or negatively charged, and they bond with the metal atom or ion through coordination bonds.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Ligands are molecules or ions that donate electron pairs to metal ions, forming coordination bonds, and they can be either neutral or negatively charged.
Assertion (A): Coordination compounds often exhibit stereoisomerism due to the different arrangements of ligands.
Reason (R): Stereoisomerism occurs when ligands are arranged differently around the central metal ion, leading to isomers with the same formula but different spatial configurations.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Stereoisomerism occurs when the spatial arrangement of ligands around the central metal ion differs, resulting in different isomers with the same chemical formula.
Assertion (A): The color of a coordination compound can be affected by the ligand field strength.
Reason (R): Strong field ligands cause a large splitting of the d-orbitals, which changes the energy gap between orbitals and influences the absorption of light.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The color of a coordination compound is influenced by the splitting of d-orbitals, and the strength of the ligand field determines the extent of this splitting.
Assertion (A): Some coordination compounds exhibit magnetic properties due to the presence of unpaired electrons.
Reason (R): Paramagnetism occurs when there are unpaired electrons in the d-orbitals of the metal ion.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Paramagnetic properties arise due to unpaired electrons in the d-orbitals, which create a magnetic moment.
Assertion (A): In coordination compounds, ligands can be classified based on their charge and bonding capabilities.
Reason (R): Ligands are categorized as either anionic, neutral, or cationic depending on their charge.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Ligands are classified as anionic, neutral, or cationic based on their charge and the way they bond to the central metal ion.
Assertion (A): Some coordination compounds exhibit optical isomerism.
Reason (R): Optical isomerism occurs when the arrangement of ligands around the central metal ion cannot be superimposed on its mirror image.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Optical isomerism arises when the coordination compound has non-superimposable mirror images due to the spatial arrangement of ligands around the metal ion.
Assertion (A): In coordination chemistry, the hybridization of the central metal ion depends on the geometry of the complex.
Reason (R): The arrangement of ligands around the central metal ion determines the geometry, which in turn affects the hybridization.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The hybridization of the central metal ion is determined by the geometry of the complex, which is influenced by the arrangement of ligands around the metal.
Assertion (A): The nature of the ligand significantly affects the properties of a coordination compound.
Reason (R): Different ligands cause different splitting of d-orbitals, which affects the color, magnetism, and stability of the compound.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The type of ligand influences the extent of d-orbital splitting, which in turn affects the compound's properties like color, magnetism, and stability.
Assertion (A): A ligand can donate electron pairs to the central metal ion through more than one atom.
Reason (R): Bidentate ligands have two donor atoms that bind to the central metal ion, forming a chelate.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Bidentate ligands have two donor atoms, allowing them to bind to the central metal ion at two sites and form a stable chelate.
Assertion (A): The stability of a coordination compound depends on the nature of the metal ion and the ligands.
Reason (R): The charge, size, and electronic configuration of the metal ion and the donor properties of the ligands influence the stability.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The stability of a coordination compound is influenced by the metal ion's properties and the ligand's ability to donate electron pairs.
Assertion (A): A complex with a coordination number of 6 generally exhibits an octahedral geometry.
Reason (R): The arrangement of six ligands around a metal ion is most stable in an octahedral configuration.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Coordination complexes with a coordination number of six generally adopt octahedral geometry for maximum ligand-metal ion stability.
Assertion (A): The charge on a complex ion depends on the charges of the metal ion and the ligands.
Reason (R): The total charge of the complex ion is the sum of the charges of the metal ion and the ligands.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: The charge of a coordination complex is determined by adding the charges of the metal ion and the ligands.
Assertion (A): The concept of ligand field theory explains the bonding in coordination compounds.
Reason (R): Ligand field theory describes how ligands affect the d-orbitals of metal ions, leading to splitting and the formation of coordination compounds.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Ligand field theory explains the interaction between ligands and the metal ion, including the splitting of d-orbitals and how this affects the properties of the coordination compound.
Assertion (A): A metal ion can have a coordination number higher than six in coordination compounds.
Reason (R): Larger metal ions or ligands can accommodate more than six ligands, resulting in a higher coordination number.
Answer: C) Assertion is correct, but Reason is incorrect.
Explanation: While some metal ions may have coordination numbers greater than six, this is rare, and only specific cases allow for coordination numbers higher than six, typically with larger ions.
Assertion (A): The arrangement of ligands in a coordination compound follows the octet rule.
Reason (R): The octet rule applies to the bonding of ligands and metal ions to achieve a stable configuration.
Answer: B) Both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
Explanation: While the octet rule governs some bonding behavior, coordination compounds often do not follow the octet rule completely due to the unique bonding properties of metal ions.
Assertion (A): The presence of ligand substitution reactions is a characteristic feature of coordination compounds.
Reason (R): Ligands in coordination compounds can be replaced by other ligands, leading to new complexes.
Answer: A) Both Assertion and Reason are correct, and Reason is the correct explanation for Assertion.
Explanation: Coordination compounds undergo ligand substitution reactions, where ligands are replaced by other ligands, leading to the formation of new complexes.