Free Master of Chemistry: Inorganic Chemistry Questions and Answers — Questions and Answers

Question 1: A metal and a chemical are combined to generate a coordination complex.

Salt
Another Metal
Ligand (Correct answer)
None of them

Correct answer: Ligand

In coordination chemistry, a ligand is a molecule or ion that binds to a central metal atom or ion to form a coordination complex. Ligands act as Lewis bases, donating one or more electron pairs to the metal center to form coordinate covalent bonds. This interaction is fundamental to the structure and reactivity of coordination compounds.

Question 2: A method of separating mixture components based on differences in their affinities for mobile and stationary phases is referred to as

Stationery phase
Liquid chromatography
Chromatography (Correct answer)
None of the above

Correct answer: Chromatography

Chromatography is a powerful analytical and preparative technique used to separate components of a mixture. It operates on the principle of differential partitioning, where components are separated based on their varying affinities for a stationary phase and a mobile phase. This difference in affinity causes components to travel at different rates, leading to their separation.

Question 3: In reality, alpha rays are

A photon
Electrons
Helium nuclei (Correct answer)
None of them

Correct answer: Helium nuclei

Alpha rays, also known as alpha particles, are a form of ionizing radiation emitted during radioactive decay. They are composed of two protons and two neutrons, which is identical to the nucleus of a helium-4 atom (He2+). Alpha particles carry a positive charge and have a relatively high mass compared to other forms of radiation.

Question 4: The substance is referred to as benzoin oxime.

Cupric acid
Dioxime (Correct answer)
Cupron
None of them

Correct answer: Dioxime

Benzoin oxime is an organic compound derived from benzoin and hydroxylamine. It is classified as a dioxime because it contains two oxime functional groups. This compound is known for its chelating properties and is often employed in analytical chemistry, particularly for the gravimetric determination of metal ions like copper.

Question 5: Select the force or forces at play in chromatography.

Electrostatic
Hydrogen Bonding
London
All of them (Correct answer)

Correct answer: All of them

Chromatography relies on a variety of intermolecular forces to achieve the separation of mixture components. These forces include electrostatic interactions (ionic attractions), hydrogen bonding, and London dispersion forces (a type of van der Waals force). The specific combination and strength of these interactions between the analytes and the stationary and mobile phases dictate the separation efficiency.

Question 6: Selected the indicator for the Cu-EDTA titration.

Murexide (Correct answer)
Thymol blue
Phenolphthalein
None of them

Correct answer: Murexide

Murexide is a widely used metallochromic indicator in complexometric titrations, particularly for the determination of metal ions such as copper (Cu2+) with EDTA. It forms a distinctively colored complex with the metal ion. At the equivalence point, EDTA displaces the murexide from the metal, causing a sharp and observable color change in the solution.

Question 7: Pick substances that can be converted into chelating agents.

Tridentate
Tetradentate
Bidentate
All of them (Correct answer)

Correct answer: All of them

Chelating agents are ligands that can form multiple coordinate bonds with a single metal ion, creating a stable, ring-like structure known as a chelate. Ligands are categorized by their denticity, which refers to the number of donor atoms they use to bind to the metal center. Bidentate (two donor atoms), tridentate (three donor atoms), and tetradentate (four donor atoms) ligands are all capable of acting as effective chelating agents.

Question 8: Which electrolyte is used for gold plating?

[K(Ag(NH3)2]
[K(Au(NH3)2]
[K(Au(CN)2] (Correct answer)
None of them

Correct answer: [K(Au(CN)2]

Potassium dicyanoaurate(I), K[Au(CN)2], is the most common and effective electrolyte used for industrial gold plating. In this complex, gold is present as the [Au(CN)2]- anion, which allows for the controlled and uniform deposition of a smooth, adherent gold layer onto a substrate through electroplating. Cyanide complexes are favored for their stability and ability to produce high-quality deposits.

Question 9: The energy difference between the t2g and eg sets is designated by in crystal field theory (CFT).

10Dq (Correct answer)
0Dq
20Dq
8Dq

Correct answer: 10Dq

In Crystal Field Theory (CFT), the energy difference between the lower-energy t2g set and the higher-energy eg set of d-orbitals in an octahedral complex is denoted as Δo (delta-octahedral) or 10Dq. This crystal field splitting energy is a crucial parameter that explains the electronic properties, color, and magnetic behavior of transition metal complexes.

Question 10: One particle is released in the initial stage of the disintegration of uranium.

Electron
Alpha particle (Correct answer)
Beta particle
Gamma particle

Correct answer: Alpha particle

Uranium-238, the most abundant isotope of uranium, primarily undergoes alpha decay as its initial mode of radioactive disintegration. During alpha decay, an alpha particle (a helium nucleus, 4He) is emitted from the nucleus, transforming uranium-238 into thorium-234. This process is the first step in the long uranium decay series.

Question 11: The coordination number of Ni +2 in [Ni(NH2-CH2-CH2-NH2)3]+2 is.

Two
Three
Five
Six (Correct answer)

Correct answer: Six

The ligand NH2-CH2-CH2-NH2 is ethylenediamine (en), which is a bidentate ligand, meaning it forms two coordinate bonds with the metal center through its two nitrogen atoms. In the complex [Ni(en)3]+2, there are three ethylenediamine ligands. Therefore, the total number of coordinate bonds formed with the Ni2+ ion is 3 ligands * 2 donor atoms/ligand = 6, making the coordination number of Ni2+ six.

Question 12: Na2[Sn(OH)6] is known by its IUPAC name.

sodium hexahydroxostannate(0)
hexahydroxostannate(IV) sodium
sodium hexahydroxostannate(IV) (Correct answer)
sodium hexahydroxostannate(I)

Correct answer: sodium hexahydroxostannate(IV)

For the compound Na2[Sn(OH)6], the cation is sodium. The anionic complex is [Sn(OH)6]2-. There are six hydroxide (OH-) ligands, so 'hexahydroxo'. To determine the oxidation state of tin (Sn), we set up the equation: Sn + 6(-1) = -2, which gives Sn = +4. Therefore, the IUPAC name is sodium hexahydroxostannate(IV).

Question 13: At pH, the copper complex is generated in ppt.

10-16
6.20-8.20
3.0-3.3 (Correct answer)
5.40-9.80

Correct answer: 3.0-3.3

The pH range of 3.0-3.3 is specific for the precipitation of certain copper complexes, particularly in analytical chemistry. For example, some organic chelating agents are used to selectively precipitate copper(II) ions within this slightly acidic pH range, allowing for its separation or quantitative determination. This is a specific condition for a particular complex formation and precipitation.

Question 14: With the exception of, all halogens can display various co-valences.

Iodine
Bromine
Chlorine
Fluorine (Correct answer)

Correct answer: Fluorine

Fluorine is unique among the halogens because it lacks available d-orbitals in its valence shell and is the most electronegative element. This prevents it from expanding its octet and forming more than one covalent bond, thus limiting its covalence to 1. In contrast, chlorine, bromine, and iodine possess accessible d-orbitals, allowing them to exhibit variable covalences and higher oxidation states.

Question 15: Which of the following compounds is more likely to be ionic?

NO2
SrBr2 (Correct answer)
CBr4
GaAs

Correct answer: SrBr2

Ionic compounds typically form between a metal and a nonmetal with a significant difference in electronegativity. Strontium (Sr) is an alkaline earth metal, and bromine (Br) is a halogen. The large electronegativity difference between Sr and Br leads to the transfer of electrons, forming Sr2+ and Br- ions, thus creating an ionic bond in SrBr2. The other compounds have more covalent character.

Question 16: Choose the methods for separating colors, amino acids, and dyes.

Crystallization
Filtration
Centrifugation
Chromatography (Correct answer)

Correct answer: Chromatography

Chromatography is an exceptionally versatile technique for separating complex mixtures, including colors, amino acids, and dyes. These substances often possess varying polarities, sizes, and chemical properties, which allow them to be differentially adsorbed onto a stationary phase and eluted by a mobile phase. This differential interaction enables their effective separation and purification.

Free Master of Chemistry: Inorganic Chemistry Questions and Answers

A metal and a chemical are combined to generate a coordination complex.