Quantum Chemistry
- Total number of nodes for 3d orbital is __
(a) 3
(b) 2
(c) 1
(d) 0
Answer: (b)
Explanation
Total number of nodes include angular and radial nodes. Angular nodes and radial nodes are given by the formula n – l -1 and l respectively. So the total number of nodes are n – l -1 + l = n – 1. For 3d orbit, “n” is 3, so total number nodes is 3 – 1 = 2.
Video Explanation - Which of the following set of quantum numbers is not valid?
(a) n = 5, l = 2, m = 0, s = 1/2
(b) n = 1, l = 2, m = 0, s = 1/2
(c) n = 5, l = 3, m = 2, s = 1/2
(d) n = 5, l = 2, m = 0, s = -1/2
Answer: (b)
Explanation
The set of quantum number n = 1, l = 2, m = 0, s = 1/2, is not valid because the value of azimuthal quantum number should lie only in between 0 and n-1, where n is principal quantum number. So the above set of quantum numbers is not valid.
Video Explanation - Write the values for l, n, and m for Ψ3,1,0?
(a) 1, 3, 0
(b) 3, 1, 0
(c) 0, 3, 1
(d) 1, 0, 3
Answer: (a)
Explanation
The representation of the Schrodinger wave function is given by Ψn,l,m. Therefore by comparing Ψn,l,m and Ψ3,1,0 we get that n = 3, l = 1 and m = 0. Here n, l, and m are principal, azimuthal and magnetic quantum numbers respectively.
Video Explanation - Which of the following is the correct form of Schrodinger wave equation?
(a) ∂2Ψ + 8π2m/h2 (E−V)Ψ=0
(b) ∂2Ψ + 8π2m2/ h2 (E−V)Ψ=0
(c) ∂Ψ2 + 8π2m/h (E−V)Ψ=0
(d) ∂2Ψ + 8π2m2/h (E−V)Ψ=0
Answer: (a)
Explanation
The Schrödinger equation is a partial differential equation that describes the dynamics of quantum mechanical systems via the wave function. The trajectory, the positioning, and the energy of these systems can be retrieved by solving the Schrödinger equation.
Video Explanation - Simultaneous determination of exact position and momentum of an electron is
(a) Possible
(b) Impossible
(c) Sometimes possible sometimes impossible
(d) None of the above
Answer: (b)
Video Explanation - Orbital is
(a) Circular path around the nucleus in which the electron revolves
(b) Space around the nucleus where the probability of finding the electron is maximum
(c) Amplitude of electrons wave
(d) None of these
Answer: (b)
Video Explanation - The maximum number of electrons which can be present in a subshell can be represented by
(a) 2l + 1
(b) 2n2
(c) 4l + 2
(d) 4l – 2
Answer: (c)
Explanation
Maximum number of electrons present in a subshell is given by the formula 4l+2, where l is the azimuthal quantum number.
Video Explanation - Which of the following quantum numbers governs the spatial orientation of an atomic orbital?
(a) Magnetic quantum number
(b) Spin quantum number
(c) Azimuthal quantum number
(d) Principal quantum number
Answer: (a)
Video Explanation - The maximum number of orbitals present in a subshell can be represented by
(a) 2l + 1
(b) 2n2
(c) 4l + 2
(d) 4l – 2
Answer: (a)
Video Explanation - The Schrodinger wave equation is
(a) Non linear differential equation
(b) linear differential equation
(c) 1st order equation
(d) All of these
Answer: (b)
Video Explanation
Named Reactions
- In Sendmeyer, reaction, which of the following is not a Chlorinating agent?
(a) Thionyl Chloride
(b) Sulfuryl Chloride
(c) Phosphorus Chlorides
(d) None of the mentioned
Answer: (d)
Explanation: Thionyl Chloride (SOCL2), Sulfuryl Chloride (SO2CL2) and Phosphorus Chlorides(PCL3, PCL5) are all used as chlorinating agents.
Video Explanation - Which Is The Best Method To Synthesize An Alkene With The Confirm Position Of Double Bond
(a) Beta Elimination Reaction
(b) Dehydrogenation Reaction
(c) Wittig Reaction
(d) Mannich Reaction
Answer: (c)
Video Explanation - In Beckmann rearrangement reactions, what types of isomers are produced?
(a) Geometrical isomers
(b) Structural isomers
(c) Optical isomers
(d) Conformational isomers
Answer: (b)
Explanation
The atoms in the products have multiple configurations or bonds, but they have the same molecular formula. Because butane and isobutane both have the same number of carbon (C) and hydrogen (H) atoms, their chemical formulae are identical
Video Explanation - Which chemical rearrangement was the first to be recognised as such by early chemists?
(a) Wolff’s rearrangement
(b) Pinacole rearrangement
(c) Favorskii rearrangement
(d) Hofmann rearrangement
Answer: (b)
Explanation
Early chemists identified the pinacol rearrangement as the first molecular rearrangement.
What is pinacol pinacolone rearrangement? The pinacol pinacolone rearrangement is an approach to convert a 1,2-diol to a carbonyl compound. It takes place under acidic conditions. The name of the reaction derives from the rearrangement of pinacol to pinacolone.
Video Explanation - Which medium is used in the benzylic acid rearrangement reaction?
(a) Neutral
(b) Strong basic
(c) Mild acidic
(d) Strong acidic
Answer: (b)
Explanation
The attack of hydroxide on one of the carbonyl groups initiates the benzylic acid rearrangement process.
Video Explanation
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- Identify the incorrect statement regarding alkadienes.
(a) Dienes show cis-trans isomerism
(b) Conjugated dienes have better stability compared to other dienes
(c) Dienophile supports alkadienes
(d) Alkadienes also undergo hydrobromination
Answer: (c)
Explanation
Dienophiles attack the performance of alkadienes rather than supporting them.
Video Explanation - Benzaldehyde can be prepared by oxidation of toluene by which of the following reagent?
(a) Acidic KMnO4
(b) K2Cr2O7
(c) CrO2Cl2
(d) basic KMnO4
Answer: (c)
Explanation
Benzaldehyde can be prepared by oxidation of toluene by CrO2Cl2.
Video Explanation - Carbylamine reaction is given by:
(a) Alipahtic primary amines only
(b) Aromatic amines only
(c) Both aromatic and aliphatic primary amines
(d) All secondary amines and diazonium salts
Answer: (c)
Explanation
Only primary amines can give carbylamine test. RNH2+CHCl3+KOH→RNC Ar−NH2+CHCl3+KOH→Ar−NC
Here, R− may be an alkyl or an aryl group.
Secondary and tertiary amines don’t give carbylamine reaction test.
Video Explanation - Gattermann reaction is given by:
(a) Benzene
(b) Toluene
(c) Cholorobenzene
(d) None of these
Answer: (a)
Video Explanation - The Best Medium For Mannich Reaction Is
(a) Acidic
(b) Basic
(c) Aqueous
(d) Organic
Answer: (a)
Video Explanation
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