Chemistry Reaction Mechanisms Quiz

The colour of potassium dichromate is caused by the transfer of electrons from the ligand to the metal.

In metal carbonyls, the CO group donates 𝜎 bonding electrons to the metal, and there is also back-bonding from the filled metal orbitals to the empty p𝜋 orbitals of CO.

The d𝜋 − p𝜋 back-bonding from the metal to the CO ligand strengthens the M-CO bond.

In the complex, the C-O bond length is shorter than in free CO gas because of the back-bonding.

NO is a neutral oxide because the oxidation states of nitrogen and oxygen cancel out. It reacts with oxygen to form nitrogen dioxide.

The Haworth projection of 𝛼-D-glucopyranose shows the anomeric hydroxyl group (OH) pointing downwards.

The anomeric carbon in 𝛼-D-glucopyranose is the carbon atom that is attached to two oxygen atoms, one in the hemiacetal ring and the other in the hydroxyl group.

The d-d transition is the electronic transition between the energy levels of the d orbitals in a metal ion. This is responsible for the colour of transition metal complexes.

Ligand-to-metal charge transfer (LMCT) involves the transfer of an electron from a ligand orbital to a metal orbital. This usually occurs when the ligand is a strong reducing agent and the metal is oxidizing.

The bond order is the average number of bonds between two atoms. In PO3-4, each P-O bond has a bond order of 1.25 because of resonance between the different possible structures. Each oxygen atom has a formal charge of -0.75. This is calculated by subtracting the sum of non-bonding electrons and half of the bonding electrons from the number of valence electrons of oxygen.

The rate-determining step is the slowest step in a reaction mechanism. In the reaction of methane (CH4) with chlorine (Cl2), the rate-determining step is the formation of the chlorine radical (Cl•) from the chlorine molecule (Cl2). This is because the chlorine radical is required to initiate the chain reaction, which leads to the formation of chloromethane (CH3Cl).

Dehydrobromination is the removal of HBr from an alkyl halide. 3-bromo-3-cyclopentylhexane can undergo dehydrobromination to form different alkenes, including geometric isomers (cis and trans isomers). There are four possible alkenes: two cis, one trans, and one non-stereoisomeric.

Aromatic nitriles are not prepared by reacting an aryl halide (ArX) with potassium cyanide (KCN). This reaction usually results in the formation of an aliphatic nitrile, not an aromatic nitrile.

The peptide bond, which links amino acids in proteins, is actually an amide bond. It forms between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of another amino acid.

The reaction of potassium dichromate (K2Cr2O7) with concentrated sulfuric acid (H2SO4) in the presence of sodium chloride (NaCl) releases chromyl chloride (CrO2Cl2) as reddish-brown fumes. These fumes, when passed through sodium hydroxide (NaOH), form sodium chromate (Na2CrO4) which is a yellow solution. The yellow precipitate formed upon the addition of acetic acid (CH3COOH) and lead acetate [(CH3COO)2Pb] is lead chromate (PbCrO4) which is yellow in colour.

The equivalent conductance at infinite dilution is a measure of the conductivity of an electrolyte. It is highest for the electrolyte which has the highest ionic mobility. The order of equivalent conductance at infinite dilution generally follows the trend: KCl > NaCl > LiCl.

Aromatic compounds are cyclic, planar, and follow Hückel's rule (4n+2 π electrons, where n is an integer). Only specific types of cations can be aromatic.

The reaction of magnesium carbide (Mg2C3) with water produces a gaseous product, identified as X. When gas X reacts with oxygen (O2), it forms carbon dioxide (CO2). The question asks for the volume of CO2 produced at standard temperature and pressure (STP).

Lower oxidation states become more stable when moving down groups 13 and 14 in the periodic table. This is attributed to the decrease in ionization energy (I.E.) and electronegativity down the group, as well as the poor shielding of valence electrons by the inner d and f orbitals.

The reaction of two molecules of reactant A with one molecule of reactant C to form a product P proceeds through a two-step mechanism. The first step involves the reversible formation of an intermediate B from reactant A, characterized by an equilibrium constant K. The second step involves the irreversible reaction of intermediate B with reactant C to form the product P, with a rate constant Kf. The question asks to express the overall rate of the reaction in terms of the rate constants and concentrations of reactants and intermediates.

The reaction sequence involves the conversion of cis-2-phenylcyclohexanol through intermediates A and B to a final product C. The question asks for the structure of product C, which is formed by the reaction of intermediate B with methyl xanthate followed by pyrolysis.

The reaction involves the treatment of an unknown species X with dilute sulfuric acid (H2SO4) to produce a colorless gas Y with an irritating smell. When gas Y is treated with potassium dichromate (K2Cr2O7) and sulfuric acid, a green solution is formed. The question asks to identify the species X and Y.

The reaction under consideration involves the reaction of an unknown species X with dilute sulfuric acid (H2SO4) to produce a colorless gas with an irritating smell, designated as Y. When gas Y is treated with potassium dichromate (K2Cr2O7) and sulfuric acid, a green solution forms. This set of reactions suggests the presence of a sulfite or sulfur dioxide. Sulfites react with dilute sulfuric acid to produce sulfur dioxide gas, which has an irritating smell. The green solution formed upon reaction with K2Cr2O7 indicates the oxidation of sulfur dioxide to sulfate, which is a common reaction for sulfur dioxide in the presence of oxidizing agents.

The reaction under investigation involves an unknown species X reacting with dilute sulfuric acid (H2SO4) to produce a colourless gas with an irritating smell, denoted as Y. Treatment of gas Y with potassium dichromate (K2Cr2O7) and sulfuric acid results in a green solution. The presence of a green solution points to the formation of a chromic ion (Cr3+), indicating that the gas Y is likely sulfur dioxide (SO2). The reaction with K2Cr2O7 oxidizes SO2 to sulfate ions (SO42-), leading to the formation of the green-coloured chromic ion. Thus, the unknown species X is likely sulfite (SO32-), as it reacts with dilute sulfuric acid to release SO2 gas.