Organic Chemistry & Atomic Structure Quiz

<p>Linear</p> Signup and view all the answers

<p>Lewis Acids</p> Signup and view all the answers

<p>Trignonal planar</p> Signup and view all the answers

<p>CnH2n-2</p> Signup and view all the answers

<p>Baeyer's Reagent</p> Signup and view all the answers

<p>n=4, l=0, m=0</p> Signup and view all the answers

<p>Pauli's exclusion principle states that no two electrons in an atom can have the same quantum numbers. This means that no two electrons in an atom can have the same combination of <code>n</code>, <code>l</code>, <code>m</code>, and <code>s</code> (spin quantum number).</p> Signup and view all the answers

<p>The electronic configuration of <code>O2</code> is: <code>(σ2s)² (σ*2s)² (σ2px)² (π2py)²(π2pz)² (π*2py)¹(π*2pz)¹</code>. The molecule has two unpaired electrons, explaining its paramagnetic nature.</p> Signup and view all the answers

<p>Lattice energy is the energy change that happens when one mole of solid ionic compound is formed from its constituent ions in the gas phase.</p> Signup and view all the answers

<p>A chiral carbon atom is a carbon atom that is bonded to four different atoms or groups of atoms. A simple example is in the molecule 2-bromobutane: <code>CH3CHBrCH2CH3</code>, where the carbon bonded to Br is a chiral carbon.</p> Signup and view all the answers

<p>The R/S notation of this molecule is (S)-2-aminopropanoic acid.</p> Signup and view all the answers

<p>Calcium carbide (CaC2) can be reacted with water to produce acetylene (C2H2). The reaction produces acetylene gas, along with calcium hydroxide (Ca(OH)2).</p> Signup and view all the answers

<p>CH3-CHBr-CH3</p> Signup and view all the answers

<p>When ethylene is treated with alkaline KMnO4 solution, it undergoes oxidation to form ethylene glycol, commonly known as 1,2-ethanediol. KMnO4 is a powerful oxidizing agent and, in alkaline conditions, cleaves the double bond in alkenes to form vicinal diols.</p> Signup and view all the answers

<p>Huckel's rule states that a cyclic conjugated system is aromatic if the number of pi electrons is equal to <code>4n+2</code>, where <code>n</code> is a non-negative integer.</p> Signup and view all the answers

<p>Heisenberg's Uncertainty Principle states that it is impossible to simultaneously know both the position and momentum of a particle with arbitrary accuracy. The more precisely you measure the position of a particle, the less precisely you can know its momentum, and vice versa. Mathematically, the uncertainty is expressed as the product of the uncertainties in position and momentum is greater than or equal to Planck's constant (h) divided by 4π.</p> Signup and view all the answers

<p>The function <code>Φ</code> refers to the wave function in quantum mechanics. The square of the wave function, <code>Φ²</code>, describes the probability density of finding an electron at a particular point in space. The value of <code>p</code> is related to the linear momentum of a particle. <code>Φ²</code> represents the electron density, while <code>p</code> is related to the momentum of the particle. Both concepts are fundamental to understanding the behavior of particles in quantum mechanics.</p> Signup and view all the answers

<p>The De Broglie equation relates the wavelength (<code>λ</code>) of a particle to its momentum (p): λ = h/p. This equation is derived from the concept of wave-particle duality, where particles can exhibit wave-like behavior. It was proposed by Louis de Broglie in 1924. Here's the derivation. First, recall the Planck-Einstein relation: E = hν. Next, substitute the expression for energy (E = p²/2m) from classical mechanics into the Planck-Einstein relation. Then, solve for <code>ν </code> and substitute it into the wave equation (<code>ν = c/λ</code>). This yields <code>λ</code> = <code>h/p</code> , the De Broglie equation. This equation bridges the gap between classical mechanics and quantum mechanics.</p> Signup and view all the answers

<p>Polarizing power is a measure of the ability of an ion or molecule to distort the electron cloud of another ion or molecule. This applies to cations, primarily. Bigger cations with lower charge density will have lower polarizing power. In contrast, smaller cations with higher charge density will have a higher polarizing power. Polarizability refers to the susceptibility of an ion or molecule to have its electron cloud distorted. Larger anions are highly polarizable as they have more disperse electron clouds. They are more polarizable because their electrons are held loosely and are more easily distorted.</p> Signup and view all the answers

<p>The ammonia molecule has a trigonal pyramidal shape. The central nitrogen atom has three bonding pairs of electrons to hydrogen atoms, resulting in a slightly bent shape. The nitrogen atom also has a lone pair of electrons that repels the bonding pairs of electrons, leading to the pyramidal structure. Due to the presence of the lone pair, the bond angle between the hydrogen atoms is a little less than <code>109.5°</code>, around <code>107°</code>.</p> Signup and view all the answers

<p>Ethyl amine is a secondary amine, while aniline is a primary amine. Both are considered to be basic, but ethyl amine is more basic than aniline. The difference in basicity is due to the presence of the phenyl group in aniline. The phenyl group in aniline is electron-withdrawing, which decreases the electron density on the nitrogen atom, making it less basic. The lone pair of electrons on the nitrogen atom is involved in conjugation with pi electrons of the benzene ring, making it less available for donation as a base.</p> Signup and view all the answers

<p>Nucleophiles (literally 'nucleus-loving') are electron-rich species with a high electron density that seek positively charged centers or electron-deficient regions in a molecule. Nucleophiles can be negatively charged ions like hydroxide ions (<code>OH⁻</code>) or neutral molecules with a lone pair of electrons, such as ammonia (<code>NH3</code>).</p> Signup and view all the answers

<p>Markownikoff's rule, which states that in the addition of a protic acid to an unsymmetrical alkene, the hydrogen atom of the acid adds to the carbon atom of the alkene that already has the greater number of hydrogen atoms. For example, in the addition of HBr to propene, the hydrogen atom adds to the terminal carbon to form 2-bromopropane, not 1-bromopropane.</p> Signup and view all the answers

<p>The Birch reduction is a reaction in organic chemistry that reduces aromatic compounds to 1,4-cyclohexadiene derivatives, using lithium metal and liquid ammonia as reagents. It is a useful method for converting aromatic rings to partially unsaturated cyclic systems with a characteristic 1,4-diene pattern.</p> Signup and view all the answers

<p>Ozonolysis is a reaction involving ozone that cleaves the double or the triple bond of alkenes and alkynes. When ethylene undergoes ozonolysis, it reacts with ozone to form an ozonide, a cyclic compound with an unstable peroxide group. This ozonide is then treated with a reducing agent like zinc and water, which breaks the ozonide down into two equivalents of formaldehyde.</p> Signup and view all the answers

<p>Quantum numbers are a set of numbers that describe the properties of an electron in an atom. There are four main types: 1) Principal Quantum Number (n): Indicates the electron's energy level and has integer values (1, 2, 3, ....). Higher <code>n</code> values represent higher energy levels. 2) Azimuthal Quantum Number (l): Describes the shape of the electron's orbital and takes on values from 0 to <code>n-1</code>. <code>l = 0</code> corresponds to an <code>s</code> orbital, <code>l = 1</code> to a <code>p</code> orbital, <code>l = 2</code> to a <code>d</code> orbital, and <code>l = 3</code> to an <code>f</code> orbital. 3) Magnetic Quantum Number (ml): Indicates the orientation of the orbital in space and has values ranging from <code>-l</code> to <code>+l</code> including 0. For example, for <code>l = 1 (p orbital)</code>, ml = -1, 0, +1, representing three different orientations of the <code>p</code> orbital (px, py, pz). 4) Spin Quantum Number (ms): Describes the intrinsic angular momentum of an electron, which is referred to as spin. It has two possible values: +1/2 and -1/2.</p> Signup and view all the answers

<p>i) de-Broglie's principle: This principle states that every particle, whether it be an electron, proton, or any other matter, can exhibit wave-like behavior. The wavelength associated with a particle (λ) is inversely proportional to its momentum (p) and is given by the equation: λ = h/p, where h is Planck's constant. This principle is significant because it leads to the understanding that matter has wave-particle duality, meaning it can behave as both a wave and a particle.<br /> ii) Hund's rule of maximum multiplicity: Hund's rule states that when filling degenerate orbitals (orbitals with the same energy levels), electrons should first be distributed one electron at each orbital before doubling up in any given orbital. This principle is essential for understanding the electronic configuration of atoms and molecules. Electrons tend to maximize their spin multiplicity (total spin angular momentum), making the atom or molecule more stable.</p> Signup and view all the answers

<p>Fajan's rule is a set of guidelines that predict whether the bond between two ions in an ionic compound will have some covalent character. It states that covalent character increases as:</p> <ul> <li>Cation size decreases: Smaller cations with higher charge density have a higher polarizing power, distorting the electron cloud of the anion and leading to more covalent character.</li> <li>Anion size increases: Larger anions are more polarizable, having a more disperse electron cloud. This makes them easier to distort by the cation's polarizing power.</li> <li>Cation charge increases: A higher cationic charge leads to a stronger attraction to the anion's electrons, increasing the covalent character.</li> </ul> <p>For example, LiF is more ionic than LiI because the I- ion is larger and more polarizable than F-. Similarly, AlCl3 is more covalent than NaCl because Al+3 has a smaller ionic radius and a higher charge than Na+.</p> Signup and view all the answers

<p>VSEPR theory (Valence Shell Electron Pair Repulsion theory) helps predict the geometry of molecules based on the repulsion between electron pairs in the valence shell of an atom, minimizing their repulsion. The central atom in H2O is oxygen. It has 2 lone pairs and 2 bonding pairs of electrons. The lone pairs repel each other more strongly than bonding pairs, making the bond angle between the two hydrogen atoms less than 109.5 degrees. This results in a bent or angular shape for the water molecule.</p> Signup and view all the answers

<p>Carbocations are positively charged carbon atoms. They are electron deficient and highly reactive intermediates in organic reactions. They are usually formed by the loss of a leaving group from carbon (e.g., deprotonation or departure of halide ions). The stability of a carbocation is determined by the number of electron-donating groups attached to the positively charged carbon. More substituted carbocations are more stable because the alkyl groups (R groups) act as electron-donating groups, helping to disperse the positive charge. The stability trend is Tertiary &gt; Secondary &gt; Primary &gt; Methyl. Tertiary carbocations are the most stable because they have three electron-donating alkyl groups.</p> <p>Carbocations can undergo various reactions, including rearrangements (e.g., hydride shift or alkyl shift) to form more stable carbocations. The stability of carbocations affects the regiochemistry (positions of new bonds) in many reactions.</p> Signup and view all the answers

<p>i) Electromeric effect: The electromeric effect is a temporary displacement of electrons in a conjugated system due to the influence of an attacking reagent. This effect is observed in conjugated systems like alkenes, alkynes, and aromatic compounds. When an electrophile (electron-seeking species) approaches a pi bond, the electron cloud of the pi bond shifts towards the electrophile, creating a temporary dipole moment. The electromeric effect is a temporary effect, lasting only as long as the electrophile is near the molecule. It plays a crucial role in directing the reactivity of conjugated systems.</p> <p>ii) Homolysis and Heterolysis:</p> <ul> <li>Homolysis is the breaking of a covalent bond where each of the bonded atoms takes one electron from the shared pair, forming two radicals. This process occurs when the bond breaks symmetrically, resulting in the formation of two free radicals.</li> <li>Heterolysis involves the breaking of a covalent bond where one of the bonded atoms takes both electrons from the shared pair. This type of bond cleavage occurs asymmetrically, resulting in the formation of a pair of ions (cation and anion). <strong>Both homolysis and heterolysis are important in organic reactions and involve the breaking of covalent bonds. These processes lead to the formation of different reactive intermediates. Homolysis leads to radicals, while heterolysis forms ions.</strong> </li> </ul> Signup and view all the answers

<p>i) Dehalogenation of tetra halides: Alkynes can be formed by removing two halogen atoms from a tetrahaloalkane. This method uses a strong reducing agent, such as zinc in the presence of a suitable solvent (ethanol). The reaction involves the removal of the two halogen atoms as a dihaloalkane. ii) Dehydrohalogenation of vicinal-dihalides: Alkynes can be synthesized by the dehydrohalogenation of vicinal-dihalides, which are compounds where two halogen atoms are attached to adjacent carbon atoms. This reaction requires a strong base like potassium hydroxide (KOH) in alcoholic solution (usually ethanol). The base removes a hydrogen atom and a halogen atom from the vicinal dihalide, resulting in the formation of a triple bond.</p> Signup and view all the answers

<p>Propyne, an alkyne, reacts with alkaline potassium permanganate (KMnO4) to form a diketone. Upon reaction with KMnO4, the triple bond in propyne breaks, and two oxygen atoms are added to the carbons that were originally part of the triple bond. This results in the formation of a dicarbonyl compound, a diketone.</p> Signup and view all the answers

<p>Saytzeff's rule states that in elimination reactions, the alkene formed is the most substituted alkene, meaning the alkene with the most alkyl groups attached to the doubly bonded carbons.<br /> During elimination reactions, like dehydrohalogenation, the base removes a proton and a leaving group, creating a double bond. This reaction can lead to the formation of different alkene products if the starting material is not symmetrical. Saytzeff's rule predicts that the more substituted alkene will be the major product. The reason is that the more substituted alkene is more stable due to the electron-donating effect of the alkyl groups, and it is favored by the reaction's thermodynamics.</p> Signup and view all the answers

<p>i) CH3-CH==CH2 + O3 -&gt; CH3-CH=O + HCHO Zn / H2O ii) CH3-CH2-Cl + KOH (Alc) -&gt; CH2=CH2 + KCl + H2O</p> Signup and view all the answers