The most stable canonical structure among all of above is:
The structure which has a maximum double bond is more stable.
Strongest base among the following species is:
Nitrogen atom is more basic than the other two oxygen and carbon. Also, it has an available lone pair.
Compare relative stability of the following structures:
Presence of negative charge on electronegative atom is more stable than that on a relatively less electronegative atom. If this is considered, negative charge on oxygen is more stable than that on nitrogen. Also, negative charge an nitrogen will be more stable than that on carbon. Hence, the order of stability is I > III > II.
Strength of following bases decrease in the order?
(I) Br- (II) F- (III) NH2 (IV) CH3-
Br- 2.96
F- 3.98
NH2, The electronegativity of Nitrogen is 3.04 and Hydrogen is 2.2 So this difference makes the N-H bond polar.
CH3 = 5.25
The ratio of van der Waal’s constant a and b, has the dimensions of:
The ratio of van der Waals’ constants a and b has the dimensions of atm L mole-1.
Hence B is the correct answer
Find the corresponding subshell utilizing the information from graph.
According to radial nodes formula:
Radial Nodes = n - l – 1
= 3 – 0 – 1
=2 nodes.
Therefore 3s.
Hence, A is the correct answer.
Distribution of molecules with velocity is represented by curve as shown:
Velocity at point A is:
Which have lowest bond angle?
PH3 because it follows Drago’s rule and hence there would be no or very low hybridization and hence pure p-orbital will be used. Therefore bond angle will be almost equal to 90 degree.
Hence C is correct.
Of the following acids, the one that is strongest is:
Higher the oxidation no. of the central atom, the stronger is the acid.
Here, Br=+7
Cl=+1
N=+3
P=+3
Thus, HBrO4 is the strongest acid amongst the given alternatives.
Lattice energy (numerical value) of chloride of alkali metals is in order:
Which of the following drawings is not a resonance structure of 1 -nitrocyclohexene:
Which of the following is not resonating structure of each other?
Molecules in option (a) are linkage isomers of each other.
According to rules of Resonance, no change in position of atom should take place.
Examine the following resonating structures of formic acid for their individual stability and then answer the question given below:
Which of the following arrangements gives the correct order of decreasing stability of the above-mentioned resonance contributors?
There are certain sets of rules that must be followed in order to check the stability of resonating structures.
These rules have a preference so we have to follow the order:
According to the above discussion, B is the correct answer.
The correct stability order of the given resonating structures is:
Valence shell = 6e-
In II, octet is incomplete
E.N : O > N
The correct sequence is: III > I > II
The correct order of stability for the given canonical structures is:
There are a certain set of rules that must be followed in order to check the stability of resonating structures.
These rules have a preference so we have to follow the order:
According to above discussion, B is the correct answer.
The correct order of stability among the following canonical structure is:
There are a certain set of rules that must be followed in order to check the stability of resonating structures.
These rules have a preference so we have to follow the order
According to above discussion, D is the correct answer.
Which of the following is most basic?
Basicity is the tendency of an atom to donate their lone pair.
In case of (a), (b),(d), lone pair of Nitrogen atom is in conjugation which is not available to be donated.
Hence (c) is more basic.
If a particle in the box of length 'l' has wavelength, ψ = (l -x)x. (x is only variable) What is its normalization constant?
Match column I with column II and select the correct answers:
The table indicates the value of van-der Waal’s constant ‘a’. The gas which can be liquefied most easily is:
rms velocity of hydrogen is √7 times the rms velocity of nitrogen. If T is the temperature of gas,then:
Copper containing alloy weighing 0.3175g dissolved in an acid, and an excess of KI is added.
Estimation of copper in alloy is based on following reactions:
Iodometric determination of copper is based on the oxidation of iodides to iodine by copper (II) ions, which get reduced to Cu+.
Comparison of standard potentials for both half reactions (Cu2+/Cu+ E0=0.17 V, I2/I- E0=0.54 V) suggests that it is iodine that should be acting as oxidizer. However, that's not the case, as Copper (I) Iodide (CuI) is very weakly soluble (Ksp = 10-12). That means concentration of Cu+ in the solution is very low and the standard potential of the half reaction Cu2+/Cu+ in the presence of iodides is much higher (around 0.88 V)
If a particle has linear momentum at position
, then its angular momentum is:
Angular momentum is equal to the cross product of the position vector and the linear mamentum.
J=r×p
(4i + 9j + 2k) × (3i - 3j + k)
= -15i-2j+39k
Consider two molecules A & B.
∠α = ∠HCH; ∠β = ∠FCF
Which of following is true?
Though the substituting atoms are different in both cases but the hybridization of carbon is the same that is sp3, having the bond angle of 109′28″.
Predict the shape of IF4+ molecule using VSEPR theory:
The electron geometry of IF4+ is trigonal bipyramidal. This is because it has five total electron groups. The central atom is bonded to four other atoms and has one lone pair of electrons. The lone pair of electrons will affect the molecular geometry of the compound as well as the bond angles.
Which of the following is true for ionization energy:
The ionization energy of molecular nitrogen is 1503 kJ/mol, and that of atomic nitrogen is 1402 kJ/mol. We conclude that the energy of the electrons in molecular nitrogen is lower than that of the electrons in the separated atoms, so the molecule is bound.
XeO2F2 has shape:
XeO2F2 molecular geometry is originally said to be trigonal bipyramidal but due to the presence of lone pair on equatorial position, the actual shape will be see-saw. The repulsion between bond pair and lone pair of electrons will be more.
What is the correct increasing order of bond lengths of bond indicated in following compund?
Arrange the following in decreasing order of their bond angles: NH3, H2O , CH4
CH4 (109.28) > NH3(107) > H2O(104.5)
The ground state electronic configuration of valence shell electrons in a molecule A2 is written as• Hence bond order is_____________________.
Bond Order =
Number of electrons in bonding MO = 8
Number of electrons in anti-bonding MO = 4
Bond order = (8 - 4)/2
Bond order = 4/2
Bond order = 2
Which of these structures is practically not a valid resonance structure for formaldehyde?
The lowest energy form is I, because every atom has a complete octet. It is the major contributor.
II is lower in energy than III, because the negative charge is in the more electronegative O atom.
Which of the following is an electrophile?
Electrophile is an electron pair acceptor. Electrophiles are positively charged or neutral species having vacant orbitals that are attracted to an electron rich centre. It participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile.
Select the correct statement:
Benzoic acid is a stronger acid than phenol because the benzoate ion is stabilised by two equivalent resonance structures in which the negative charge is present at the more electronegative oxygen atom.
The conjugate base of phenol, a phenoxide ion, has non-equivalent resonance structures in which the negative charge is at the less electronegative carbon atom. Thus, the benzoate ion is more stable than phenoxide ion. Hence, benzoic acid is a stronger acid than phenol.
An operator ‘A’ is defined as Which one of the following statement is true?
Identify which of the following operator is Hermitian:
Which of the following is/are true about zero point energy?
Zero-point energy (ZPE) is the lowest possible energy that a quantum mechanical system may have. Unlike in classical mechanics, quantum systems constantly fluctuate in their lowest energy state as described by the Heisenberg uncertainty principle.
Which of the following is/are true about Uncertainty principle:
A) As uncertainity principle tells us about the minimum uncertain value of position for a certain value of momentum or vice versa. Hence it doesn't put an upper but a lower bound.
B) The equation, is true under all conditions because it is the law of nature if anything exist it should have a certain amount of uncertainity relation, however it could be small in the bigger objects but it exists.
C) Both position and momentum are inversely proportional to each other .
D) If one of them become zero then the other should go infinity at the same time .
Which of the following is not a disproportionation reaction?
A disproportionation reaction is when a multiatomic species whose pertinent element has a specific oxidation state gets oxidized and reduced in two separate half-reactions, yielding two other products containing the same pertinent element.
Consider the following cases:
(I) 60g CH3COOH (II) 3g HCHO (III) 60g NH2CONH2 (IV) 180g C6H12O6
Percentage of carbon is identical in:
Percentage of an atom in any molecule can calculated by formula: n x (atomic weight/molecular weight) x 100
where n is total number of atomsin molecule
(i) 60g CH3COOH
Atomic weight of carbon = 12
Molecular weight = 60
Number of atoms = 8
Percentage of atom = n x (atomic weight/molecular weight) x 100
Percentage of atom = 8 x (12/60) x 100
Percentage of atom = 160
(ii) 3g HCHO
Atomic weight of carbon = 12
Molecular weight = 30
Number of atoms = 4
Percentage of atom = n x (atomic weight/molecular weight) x 100
Percentage of atom = 4 x (12/30) x 100
Percentage of atom = 160
(iii) 60g NH2CONH2
Atomic weight of carbon = 12
Molecular weight = 62
Number of atoms = 8
Percentage of atom = n x (atomic weight/molecular weight) x 100
Percentage of atom = 8 x (12/62) x 100
Percentage of atom = 154.2
4) 180g C6H12O6
Atomic weight of carbon = 12
Molecular weight = 180
Number of atoms = 24
Percentage of atom = n x (atomic weight/molecular weight) x 100
Percentage of atom = 24 x (12/180) x 100
Percentage of atom = 160
In trigonal bipyramidal geometry, which of the following holds true?
The axial bonds are longer than equatorial bonds because of greater repulsion from equatorial bonds. The 2-axial bonds are at 90º degree angle to 3-equatorial bonds while all equatorial bonds are at 120º angle to each other. So, none of the statements is correct hence option(d)
Total number of nucleophiles among following molecules is/are___________.
CH3O-, carbene, Nitrene, H2O , ROH, ZnCl2, NHR2, SnCl4, -NH2 , Cl-.
Total number of a-hydrogen in the given following compound is:
Number of carbenes among following:
:HgCl2, :CCl2 , , :CCl3, :SnCl2, BeCl2, :CH2.
A carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is R-(C:)-R' or R=C: where the R represent substituents or hydrogen atoms.
A particle having energy 66h2/8mL2 for a 3D box has degeneracy?
Find ΔE for states n = 3,4 in Bohr’s model of hydrogenic atoms (in eV):
ΔE = 13.6 [ 1/9 - 1/16]
ΔE = 13.6 [7/144]
ΔE = 13.6 x 0.048
ΔE = 0.66
By what factor does the average velocity of a gaseous molecule increase, when temperature is doubled:
What is the value of PV/nRT for ideal gas?
Ideal gas equation, PV = nRT
Dividing both sides by nRT
⇒ PV/nRT = nRT/nRT
⇒ PV/nRT = 1
Normality of a solution obtained by mixing 10 mL of N/5 HCl & 30 mL of N/10 HCl is_______:
Ca(OH)2 + H3PO4 → CaHPO4 + 2H2O
Equivalent weight of H3PO4 in the above reaction is:
H3PO4 is an acid and the equivalent mass of an acid is calculated by using the formula:
From the given reaction:
Ca(OH)2 + H3PO4 → CaHPO4 + 2H2O
As, the replaceable hydrogen ions in acid is 2, by putting the values in above equation, we get:
Hence, The equivalent mass of H3PO4 for the given reaction is 49 g eq.
How many equivalents are there per mol of H2S in its oxidation to SO2?
Total number of the molecules that violates the rules of resonance are__________________
In the above structure Nitrogen is having 5 bonds which is not possible, hence these molecules are violating the rules of resonance.
In above molecule Oxygen is forming 4 bonds that is not possible, hence this molecules is also violating the rules of resonance.
In both molcules electron pair is moving from Sulphur and Oxygen which already have positive charge. Also in case of 2nd molecule, Oxygen is forming 5 bonds which is again not possible.
Total number of delocalized lone pairs (combined) in Adenine & Guanine:
Number of electrophiles in following:
BF3, +CH3, -NH2, I+, PCl5, NH3, OH2, SnCl4, ROR
Find the probability of finding an e- in a box of length ‘L’ in middle half of box. (in %)
At what temperature (in K), will the total KE of 0.30 mole of He be same as the total KE of 0.40 mole of Ar at 400 K?
What is the value of n2?
[Given is the wavefunction for a particle in 1-D box of length ‘L' If energy of ‘nth’ state is given by
Number of molecules in 1L of water at 4°C is close to: (Give the multiple of NA)
1 lit = 1000 cm3 = 1000 × 1 g = 1000 g = 1000/18 mol =55.5556 mol . It Contain 55.5556 N(A) number of molecule.
Consider AB2 molecule Calculate % s-character in A—B bond:
From Bent’s Rule equation, cosx = s/s-1
where x is an bond angle and s is the % s character in the bond, it is clear that if we increase bond angle, the %s Character will be maximum.
Here angle is 150,
⇒ Cosx = s/(s-1)
⇒ Cos 150° = s/(s-1)
⇒ -0.86 = s/(s-1)
⇒ -0.86s +0.86 = s
⇒ 0.86 = 1.86s
⇒ s = 0.86/1.86
⇒ s = 0.462
⇒ %s = 0.462 X 10
⇒ %s = 46.2%
Number of π-bonds in will be:
Concentration of 10% CH3COOH (w/v) in mol L-1 will be ________?
M.W of acetic acid is 60 gm
10% (w/v) acetic acid means.
In 100 ml solution acetic acid is = 10 gm
so, in 100 ml solution acetic acid is = 10/60 mole.
so. in 1000ml solution acetic acid is = (0.167 × 1000)/100
= 1.67 mole / lit
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Test | 60 questions | 180 min
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Test | 60 questions | 180 min
Test | 60 questions | 180 min
Test | 60 questions | 180 min