MCQ Questions

Answer: (b) 0.16 m/s

Answer: (c) 2n

Answer: (c) 2 cm

Answer: (c) 2 sec

Answer: (d) Zero

Answer: (b) 3 k/2

Answer: (a) Kinetic energy increases, potential increases decreases

Answer: (a) parabolic

Answer: (c) 1.44 m

Answer: (b) Increase

Answer: (b) Decrease

Answer: (c) amplitude tends to infinity at resonance

Answer: (a) parabolic

Answer: (a) Greater than T.

Answer: (b) 0.16 m/s

Answer: (b) 1/∏

Answer: (c) remains the same

Answer: (c) -mg sinθ

Answer: (c) A body in S.H.M. its acceleration more at extreme position its directions away from mean position

Answer: (d) 19 : 9

Answer: (c) a sin (wt – kx)

Answer: (d) Stationary wave

Answer: (b) Energy is minimum at nodes and maximum at antinodes

Answer: (b) 0.5 sec

Answer: (c) y = ym log (x – nt)

Answer: (b) 3.3 kilo cycles per second

Answer: (c) 20%

Answer: (b) Parallel to propagation

Answer: (d) Both (b) and (c)

Answer: (c) 260, 250

Answer: (a) 25 kg

Answer: (c) 1 : 2 : 3 : 4

Answer: (d) 196 Hz

Answer: (c) 480 Hz

Answer: (d) Metal

Answer: (b) Density and elasticity of ga

Answer: (b) 2 beats per second with intensity ratio (49/1) between maxima and minima

Answer: (b) Energy is minimum at nodes and maximum at antinodes

Answer: (c) 11 : 12

Answer: (b) 2 cm

Answer: (c) Fe₂ (So₄)₃
Explanation:
Iron (III) sulfate (or ferric sulfate), is the chemical compound with the formula Fe₂(SO₄)₃. Usually yellow, it is a salt and soluble in water.

Answer: (a) 26.89
Explanation:
Atomic weight = (Equivalent weight × Valency)
= (8.9 × 3) = 26.7
(Valency = (26.89)/(8.9) ≈ 3).

Answer: (b) 21
Explanation:
21 atoms are present in the compound CuSO₄. 5H₂O.

Answer: (a) 10
Explanation:
(1/2)th if mass of carbon atom weighs exact as 1 gm as from (1 × 12)/ (12) = 1 amu.
Therefore 10 times of this would be = (10 × 1) = 10 gms.
Hence 10 g would be the molar mass of that atom.

Answer: (a) 81.398 g
Explanation:
Pure ethyl alcohol
= (81.4 – 0.002)
=81.398.

Answer: (d) I₂
Explanation:
Sublimation is going directly from the solid to vapor state without passing through the liquid state. The classic demonstration of sublimation is iodine crystals. Heat them at one end of a sealed tube with the other end cooled. We get a beautiful violet vapor and can watch the iodine crystals form from the vapor in the cool end. Let us Wait for some time and all the solid iodine will disappear in the hot end and reappear as beautiful black crystals in the cold end.

Answer: (b) 4 g atom of Hydrogen
Explanation:
1 mole of CH₄ contains 4 mole of hydrogen atom i.e. 4g atom of hydrogen.

Answer: (d) 10^-21
Explanation:
1 zepto =10^-21

Answer: (a) 24 g of C (12)
Explanation:
Number of atoms = (number of moles × Avogadros number (N A) )
⇒ Number of atoms in 24 g C
= (24/12) × N A= 2N A
Number of atoms in 56 g of Fe
= (56/56) N A = N A Number of atoms in 27 g of A1
= (27/27) N A = N A Number of atoms in 108 g of Ag
= (108/108)N A = N A
Hence, 24 g of carbon has the maximum number of atoms.

Answer: (c) Constant Composition
Explanation:
The H : O ratios in water is fixed, irrespective of its source. Hence it is law of constant composition

Answer: (c) 4
Explanation:
Because 100 gm Hb contains = 0.33 gm Fe
Therefore, 67200 gm Hb = (67200 × 0.33)/ (100 gm)
Fe gm atom of Fe = (672 × 0.33)/(56)
= 4.

Answer: (a) Anion
Explanation:
A charged particle, also called an ion, is an atom with a positive or negative charge.
This happens whenever something called an ionic bond forms.
Two particles that have different numbers of electrons (the smallest particle in an atom which is negative) start reacting to each other.
The particle that has the greater amount of electrons takes the other particles electrons.
One becomes positive because it lost an electron, and the other negative because it got another electron.
The two particles become attracted to each other and mix together, making a new kind of particle.

Answer: (b) 8.0 g Methane
Explanation:
6 g carbon
Moles of carbon = (6/12) = 0.5 mol
Number of carbon atoms
= 0.5 × N_A =0.5N_A (N_A is Avogadro number)
6 g ethane (C₂H₆ two atoms of C per mole)
Moles = (6/30) = 0.2 mol
Number of carbon atoms = 0.2 × 2 × N_A = 0.4 N_A
(Number of carbon atoms = moles of compound X number of C atoms per mol × Avogadro number)
8 g methane (CH₄)
Moles = (8/16) = 0.5 mol
Number of carbon atoms = 0.5 × 1 × N_A = 0.5 N_A
21 g propane (C₃H₈)
Moles = (21/44) =0.48 mol
Number of carbon atoms = 0.48 × 3 × N_A = 1.44 N_A
28 g CO
Moles = (28/28) =1 mol
Number of carbon atoms = 1 × 1 × N_A = N_A

Answer: (a) 39.9 g
Explanation:
Molar gas volume at STP is:
1 mole = 22400 cm³ = 22.4 litres
Density = (mass / volume)
Density = 1.78 g/litre
Volume = 22.4 litres
Mass = (volume × density)
(1.78 × 22.4) = 39.872 g

Answer: (d) 0.1
Explanation:
Molarity = (number of moles of solute / volume of solution in litres)
Here number of moles = (given mass of solute / molar mass)
whereas Normality = ( Number of gram equivalent / volume of solution in liter )
where gram equivalent = ( mass of solute / equivalent mass )
Consider an example of H₂SO₄ whose molar mass = 98 g per mole
Consider a Solution containing 0.98 g of sulphuric acid in 100 ml.
Volume = 100 ml = 0.1 l
Then,
Number of moles = (0.98 / 98)
Number of moles = 0.01
Hence molarity = (0.01 / 0.1) = 0.1 M
Hence Molarity = 0.1 M
Now sulphuric acid is dibasic therefore
Its equivalent weight = (98 / 2)
Hence equivalent weight = 49
So the gram equivalent = (0.98 / 49) = 0.02
Now Normality = (0.02 / 0.1)
Hence the Normality is equal to 0.2 N.
Thus for H₂SO₄ (i.e. dibasic) Normality is 0.2 N and molarity is 0.1 M.

Answer: (c) Ion
Explanation:
A charged particle, also called an ion, is an atom with a positive or negative charge.This happens whenever something called an ionic bond forms. Two particles that have different numbers of electrons (the smallest particle in an atom which is negative) start reacting to each other. The particle that has the greater amount of electrons steals the other particles electrons. One becomes positive because it lost an electron, and the other negative because it got another electron. The two particles become attracted to each other and mix together, making a new kind of particle.

Answer: (b) Law of Conservation of Mass
Explanation:
Balanced chemical equation: A chemical equation in which the number of atoms of reactants and the number of atoms of products is equal is called a balanced equation. Every chemical equation should be balanced because:
i) According to the law of conservation of mass, atoms are neither created not destroyed in chemical reactions.
ii) It means the total mass of the products formed in a chemical reaction must be equal to the mass of reactants consumed.

Answer: (c) Constant Composition
Explanation:
The H : O ratios in water is fixed, irrespective of its source. Hence it is law of constant composition

Answer: (b) Molecular
Explanation:
Molecular formulas indicate the simple numbers of each type of atom in a molecule, with no information on structure. For example, the empirical formula for glucose is CH₂O (twice as many hydrogen atoms as carbon and oxygen), while its molecular formula is C₆H₁₂O₆ (12 hydrogen atoms, six carbon and oxygen atoms).

Answer: (d) 26.7
Explanation:
Atomic weight = (Equivalent weight × Valency)
=(8.9 × 3) = 26.7
(Valency = (26.89)/(8.9) ≈ 3).

Answer: (a) Cu⁺², Ti⁺³
Explanation:
₂₉Cu = [Ar] 3d¹⁰ 4s₁
Cu²⁺ = [Ar] 3d⁹ (n = 1)

₂₂Ti = [Ar] 3d² 4s²
Ti³⁺ = [Ar] 3d² (n = 1)

Both of these ions have one unpaired electron, hence these have same paramagnetic moment.

Answer: (b) Half
Explanation:
Let charge of proton be +e, then charge of alpha particle will be + 2e. Similarly let mass of proton be m, then mass of alpha particle will be 4m.
Now, specific charge = (charge) / (mass of the substance.)
For proton, specific charge = (e/m)
For alpha particle, specific charge = (2e)/ (4m)
Therefore there ratio is: (e/m) × (4m)/ (2e) = 2 : 1

Answer: (d) 4 × 10⁴ cm^-1
Explanation:
Frequency ν = 12 × 10¹⁴s^-1 and
velocity of light c = 3 × 10¹⁰ cms^-1.
We know that the wave number ν^– = (v/c)
= (12 × 10¹⁴)/(3 × 10¹⁰)
= 4 × 10⁴ cm^-1

Answer: (d) (d) and (e)
Explanation:
In the absence of magnetic and electric fields, the orbitals defined by magnetic quantum number are degenerate (of same energy). So, energy of the orbital, in the absence of magnetic and electric fields depends on the (n + l) value.
Higher the (n + l) value, larger the energy of the orbital.
Orbitals with same n and n + 1 values are degenerate and have same energy.
In the given combinations, d and e have same n and n + l value and so, have same energy in the absence of magnetic and electric fields.

Answer: (a) Li²⁺
Explanation:
(1/λ) = Z²R_H [(1/n₁²) – (1/n₂²)], n₁ = 1, n₂ = 2
Therefore, (1/ λ) = Z²R_H [(1/1) – (1/4)]
= (3/4) Z²R_H
λ ∝ (1/Z)²
Therefore, Li²⁺ will produce shortest wave length.

Answer: (a) 1.51 eV
Explanation:
En = (13.6)/(n²) eV
or E = (13.6)/(9)eV
= 1.51 eV

Answer: (d) Chadwick
Explanation:
The essential nature of the atomic nucleus was established with the discovery of the neutron by James Chadwick in 1932 and the determination that it was a new elementary particle, distinct from the proton.

Answer: (c) 50
Explanation:
The maximum number of electrons that can occupy a given energy level n is given by
max. no. of electrons = 2n²
So the number of orbitals that are present in an energy level n is given by
of orbitals = n²
Also a given orbital can hold a maximum of 2 electrons, which is why the maximum number of electrons that can be added to a given energy level n is twice the number of orbitals present on said energy level.
According to given,
n = 5, it refers to the fifth energy level, holds
of orbitals = 5²
of orbitals = 25
This means that the maximum number of electrons that can be added to the fifth energy level is
max no. of electrons = 2 × 25
= 50 electrons

Answer: (c) 5s
Explanation:
According to the Aufbaus principle, electron will be first enters in those orbital which have least energy. So decreasing order of energy is 5p > 4d > 5s.

Answer: (a) 1.05 × 10^-34 Jsec
Explanation:
Electron after absorbing 10.2 eV energy goes to its first excited state (n = 2) from ground state (n = 1).
Therefore, Increase in momentum = (h)/(2π)
= (6.6 × 10^-34)/ (6.28)
= 1.05 × 10^-34 Js.

Answer: (d) 9.84 × 10⁵J mol^-1
Explanation:
Energy required when an electron makes transition from n = 1 to n = 2
E₂ = −(1.312 × 10⁶ × (1)²)/(2²)
= −3.28 × 10⁵J mol^-1
E₁ = −1.312 × 10⁶J mol^-1
ΔE = E₂ − E₁
= −3.28 × 10⁵ – (−13.2 × 10⁶)
ΔE = 9.84 × 10⁵J mol^-1

Answer: (b) 7
Explanation:
For n = 4 and l = 3, the orbital is 4f.
Number of values of m= no. of orbitals= (2l + 1) = 7.

Answer: (c) 14
Explanation:
n = 4, so 4th shell and l = 3 so it is f subshell.
Thus n = 4, l = 3 indicates 4f orbitals.
In f subshell there are 7 orbitals and each orbital can accommodate a maximum of 2 electrons. So, maximum no. of electrons in 4f subshell = 7 × 2 = 14.

Answer: (b) n = 2, Be³⁺
Explanation:
r = (r₀) × (n²/Z) Å
whereas,
r₀ = radius of 1st Bohrs orbit of hydrogen atom = 0.529 Å
For r = r₀^–
(n²/Z) = 1
n² = Z (1)
Because for n = 2 , Be⁺³
Z = 4, which satisfies equation (1).
Hence, n = 2,Be⁺³ will have the same radius of 1 st Bohrs orbit of a hydrogen atom.

Answer: (c) Orientation of orbitals
Explanation:
The magnetic quantum number specifies orientation of orbitals.

Answer: (b) 5 → 2
Explanation:
Since the line in hydrogen spectrum lies within visible region that is at red end, therefore it is corresponds to the Balmer series.
The line at the red end suggests that
The first line of Balmer series is n = 3 to n =2
The second line of Balmer series is n = 4 to n = 2
The third line of Balmer series is n = 5 to n = 2

Answer: (b) 15
Explanation:
The configuration of
₂₄Cr is 1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁵, 4s¹
Therefore, total s-orbitals = 4
total p-orbitals = 6
total d-orbitals = 5 and thus
Thus, total orbitals = 4 + 6 + 5 = 15.

Answer: (c) 10 electrons
Explanation:
n = 6, ℓ = 2 means 6d → will have 5 orbitals.
Therefore max 10 electrons can be accommodated as each orbital can have maximum of 2 electrons.

Answer: (c) n = 3, l = 2, m = 1, s = + 1/2
Explanation:
n = 3, l = 0 represents 3s orbital n = 3, l = 1 represents 3p orbital n = 3, l = 2 represents 3d orbital n = 4, l = 0 represents 4s orbital The order of increasing energy of the orbitals is 3s < 3p < 4s < 3d.

Answer: (d) 4 × 10¹
Explanation:
λ = (c/v) = (3 × 10⁸)/(8 × 10¹⁵)
= 3.75 × 10^-8
= 3.75 × 10^-8 × 10⁹ nm
= 4×10¹ nm.

Answer: (b) 15, 5 and 3
Explanation:
Atomic number (Z) = 15 = P → [Ne] 3s² 3p³
Phosphorus belongs to 15th group
Number of valence electrons 3s² 3p³ = 5 and valency = 3 in ground state.

Answer: (d) Many metals with catalytic properties
Explanation:
Many metals with catalytic properties because (i) They provide surface area for reaction to occur (ii) They decreases the ionisation energy. (iii) They have vacant d-orbitals.

Answer: (b) Xe
Explanation:
Xe has the highest atomic size and molecular weight. Hence, it has strong Vander Waals forces of attraction. Hence, it has the highest boiling point.

Answer: (d) The ratio of their charge and size (i.e. charge density) is nearly the same
Explanation:
The chemistry of lithium is very similar to that of magnesium even though they are placed in different groups because of diagonal relationship.

Answer: (b) N^3-, F^–, Na⁺
Explanation:
Isoelectronic species are the neutral atoms, cations or anions of different elements which have the same number of electrons but different nuclear charge.
Number of electrons in N^3- = 7 + 3 = 10.
Number of electrons in F^– = 9 + 1 = 10
Number of electrons in Na⁺ = 11 – 1 = 10.

Answer: (d) Fe²⁺
Explanation:
Mg²⁺: 1s² 2s² 2p⁶: no unpaired electron
Ti³⁺: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹: one unpaired electron
V³⁺: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹: two unpaired electrons
Fe²⁺: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶: four unpaired electrons

Answer: (d) Sixth
Explanation:
16-1s²2s²2p⁶3s²3p⁴ there are 6e^– in outer most shell therefore its group is VIth A

Answer: (c) s and p – Block
Explanation:
Elements in which all the inner shells are complete but outer shell is incomplete is known as representative elements i.e. Those elements which have less than 8 electrons in outermost shell are representative.
s and p block elements except inert gas is known as representative elements.

Answer: (c) Elements with atomic no. 17 and 53
Explanation:
Atomic no. 17(Cl) and 53 (I) are present in the same group

Answer: (d) Fluorine.
Explanation:
Fluorine is the most electronegative element. Fluorine has an electronegativity of 3.98 on the Pauling Electronegativity Scale and a valence of 1. A fluorine atom needs one electron to fill its outer electron shell and achieve stability, which is why free fluorine exists as the F^– ion.

Answer: (b) Ar
Explanation:
In the third period of the Periodic Table the element having smallest size is Ar.

Answer: (c) Na
Explanation:
Sodium has 11 electrons which can be written as (2, 8, and 1). Its outer orbit has 1 electron When it is ionized for the first time, the outer most electron is removed very easily, so that it can form the electronic configuration of the nearest inert gas Neon (2, 8).
Neon has 8 electrons in its outermost orbit. Thus it is highly stable. Now, when the second electron is removed, a very very high amount of energy is required because it doesnt want to give away one of its outermost electron by disrupting its stability.
Thus, second ionization energy of sodium is extremely high.

Answer: (b) Metallic Character
Explanation:
The IE, EA increases along the period. The valency initially increases then decreases. The metallic character decreases along the period.

Answer: (a) Bi < P < S < Cl
Explanation:
Increasing order of electronegativity is Bi < P < S < Cl.

Answer: (a) SnO₂
Explanation:
CaO is basic; CO₂ is acidic; SiO₂ is weakly acidic. SnO₂ is amphoteric.

Answer: (d) Stability of +2 oxidation state increase
Explanation:
As we go down the group inertness of ns² pair increase hence tendency to exhibit +2 oxidation state increases and that of +4 oxidation state decreases.

Answer: (d) He, Ne, Ar, Kr
Explanation:
All the noble gases occupy the peaks of I.E. curve.

Answer: (d) atomic numbers
Explanation:
The Periodic Law states that the physical and chemical properties of the elements recur in a systematic and predictable way when the elements are arranged in order of increasing atomic number.

Answer: (b) 15, 5 and 3
Explanation:
Atomic number (Z) =15 =P → [Ne] 3s² 3p³
Phosphorus belongs to 15th group
Number of valence electrons 3s² 3p³ = 5 and valency = 3 in ground state.

Answer: (c) 1s², 2s2p⁶, 3s²
Explanation:
1s², 2s2p⁶, 3s² – In III transition e^– is to be removed from stable configuration.

Answer: (a) 0
Explanation:
BrF₅ has octahedral geometry and square pyramidal shape.
It has one lone pair and five bond pairs. So, geometry will be octahedral. But since lone pair repels too much, all the four bond pairs that had to be on a square planar surface, will tilt. This will result in a destructed geometry.

Answer: (a) sp²
Explanation:
The hybridisation of sulphur in SO₂​ is sp². Sulphur atom has one lone pair of electrons and two bonding domains. Bond angle is <120° and molecular geometry is V-shape, bent or angular

Answer: (b) sp and sp²
Explanation:
Allene: H₂​C = C = CH₂. The central carbon is attached to other carbons by two sigma and two pi bonds so its hybridisation will be sp. The terminal carbon is attached to other carbon and hydrogen by 3 sigma and 2 pi bonds and hence, its hybridisation will be sp²

Answer: (c) sp³, 0
Explanation:
The central atom of POCl₃ that is P has sp3 hybridization and the number of lone pairs over the central atom in POCl₃ is zero.

The central atom is P, which has 5 valence electrons. Out of them, two valence electrons are used to form a P = O double bond, while the other 3 valence electrons are used to form 3 P-Cl bonds. The molecular geometry of POCl₃ is tetrahedral with asymmetric charge distribution around the central atom. Therefore this molecule is polar. The structure of this compound is tetrahedral and hybridisation of P is sp³.

On the central atom P, there are 4 bonding electron clouds (1 P = O double bond and 3 P-Cl bonds) but no lone pair of electrons.

Answer: (d) K⁺ < Ca²⁺ < Mg²⁺ < Be²⁺
Explanation:
High charge and small size of the cations increases polarisation.
As the size of the given cations decreases as
K⁺ > Ca²⁺ > Mg²⁺ > Be²⁺
Hence, polarising power decreases as K⁺ < Ca²⁺ < Mg²⁺ < Be²⁺

Answer: (c) Acetonitrile
Explanation:
Acetonitrile does not contain sp² hybridized carbon.

Answer: (c) O₂^–
Explanation:
O₂^–(17)Super oxide has one unpaired electron. Since Paramagnetism is shown by those molecules which have at least one unpaired electron, hence, O₂^– is paramagnetic.
Option 1)
NO⁺
This solution is incorrect
Option 2)
CO
This solution is incorrect
Option 3)
O₂^–
This solution is correct
Option 4)
CN^–
This solution is incorrect

Answer: (c) Triangular
Explanation:
When three electrons pairs get as far apart from each other, a trigonal planar structure is formed. The bond angle in this structure will be 120°.

Answer: (b) A₂ B₃
Explanation:
A has 3 electrons in outermost orbit and B has 6 electrons in its outermost orbits. So A can give three electrons to complete its octet and B needs 2 electrons to complete its octet. So 2 atoms of A will release 6 electrons and 3 atoms of B will need six electrons to complete their octet
So, the formula will be A₂​B₃

Answer: (b) SF₄
Explanation:
Bond angle is determined by the hybridization.
SO₂ ​ undergo sp3 hybridization and exhibits 109° bond angle
BBr₃​ undergo sp2 hybridization and exhibits 120° bond angle
CS₂​ undergo sp hybridization and exhibits 180° bond angle.
SF₄​ undergo sp3 d hybridization and exhibits different bond angles.
So, the least bond angle is exhibited by CS₂

Answer: (c) NaCl
Explanation:
The highest melting point will be NaCl, it is because, the lattice energy decreases as the size of alkali metal increases so going down the group the melting point decreases, but due to the covalent bonding in LiCl, its melting point is lower than NaCl and so NaCl is expected to have maximum melting point in the alkali chlorides.​

Answer: (d) Ice
Explanation:
Ice is held together by hydrogen bonds.

Answer: (d) NO⁺ and CN⁺
Explanation:
CN⁻ and NO⁺ are isoelectronic 14 and have same bond order.

Answer: (c) HCl and He atoms
Explanation:
HCl is polar (μ ≠ 0) and He is non-polar (μ = 0) gives dipole-induced dipole interaction.

Answer: (b) sp and sp²
Explanation:
Allene: H₂​C = C = CH₂. The central carbon is attached to other carbons by two sigma and two pi bonds so its hybridisation will be sp. The terminal carbon is attached to other carbon and hydrogen by 3 sigma and 2 pi bonds and hence, its hybridisation will be sp²

Answer: (c) Molecular Solids
Explanation:
Molecular solids are the weakest.
Because Ionic solids and metallic solids are a type of bond. Bonds are stronger than Van der Waals forces.

Answer: (b) sp²
Explanation:
sp² hybrid structures have trigonal planar geometry, which is two dimensional.

Answer: (c) 16.66
Explanation:
μ_ionic = (1.6 × 10⁻¹⁹ C)(1.25 × 10⁻¹⁰ m)/(3.335 × 10⁻³⁰) (Cm/D)
= 5.99 D
%ionic character = (100 × μ_obs)/ (μ_ionic)
=100 × 15.99 = 16.66%

Answer: (b) One sigma, two pi
Explanation:
A single bond between two atoms is always considered as sigma bond.
A double bond between two atoms is always considered as one sigma and one pi bond
A triple bond between two atoms is always considered as one sigma bond and two pi bonds.
So according to the given structure CaC₂ (Calcium carbide) has 1 sigma and 2 pi bonds

Answer: (b) BeCl₂
Explanation:
Ionic or electrovalent bonds are called non-directional bonds, the meaning of non-directional is that these type of bonds does not have any special type of geometry, that is only attraction of positive and negative charge as we know ionic bonds made between metal[positively charged] and non-metal[negatively charged]

RbCl is ionic compound and non-directional