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The correct CHOICE is (b) INTERMOLECULAR, intermolecular

For EXPLANATION I WOULD say: The presence of hydrogen between MOLECULES is intermolecular hydrogen bond and the presence of hydrogen bond in the molecule itself is intramolecular hydrogen bond. So it’s intermolecular in case of alcohol and water.

The correct option is (a) True

Best EXPLANATION: Yes, in the formation of a hydrogen bond, the electron pair moves away from hydrogen. This OCCURS due to the HIGH electronegativity of other atoms participating in a hydrogen bond. So NATURALLY, hydrogen has positive CHARGES and electrons move away.

The correct choice is (b) Oxygen

The explanation is: Most ELECTRONEGATIVE ELEMENTS can only form hydrogen bonds with hydrogen, Among Sodium, Oxygen, Aluminium, and RUBIDIUM, Oxygen is the electronegative ELEMENT. So only oxygen can form a hydrogen BOND.

Correct OPTION is (c) NaCl

For EXPLANATION I would say: Water, Hydrogen fluoride INCLUDE intermolecular hydrogen while o-nitrophenol has INTRAMOLECULAR hydrogen bonding. Sodium Chloride NaCl has an ionic bond that is MUCH stronger than hydrogen bond.

Right choice is (d) PHYSICAL state

Easy explanation: The MAGNITUDE of the H-bonding depends on the physical state of the COMPOUND. In the gaseous state, it is minimum and in the solid state, it is maximum. There is a great influence on a compound’s STRUCTURE and PROPERTIES.

The correct choice is (a) intermolecular

For explanation I would say: In a water MOLECULE, the HYDROGEN bonds are formed between other MOLECULES but not within the same molecule. The presence of hydrogen between molecules is intermolecular hydrogen bond and presence of hydrogen bond in the molecule itself is INTRAMOLECULAR hydrogen bond.

The CORRECT option is (a) True

For EXPLANATION I WOULD say: IN the HYDROGEN bond, the other element is highly electronegative, So the hydrogen becomes electropositive comparatively in this case and there is a displacement of electrons towards the electronegative SIDE. Hence hydrogen has a positive charge.

Correct CHOICE is (c) Hydrogen bond

To ELABORATE: For example, consider a molecule that’s FORMED due to a covalent between hydrogen and fluorine. Here hydrogen acquires a positive charge. Hydrogen bond FORMATION occurs between hydrogen in a molecule and fluorine of the other molecule.

Correct ANSWER is (B) intramolecular

For explanation I WOULD say: The presence of hydrogen between molecules is INTERMOLECULAR hydrogen BOND and presence of hydrogen bond in the molecule itself is intramolecular hydrogen bond. In o-nitrophenol, there is a hydrogen bond between the hydrogen of the hydroxide group and oxygen.

Correct option is (a) electronegative

The EXPLANATION is: Electronegativity is the tendency of a neutrally isolated GASEOUS atom to attract an electron. This is high in the case of nitrogen, oxygen, and fluorine. So the NEGATIVE CHARGE in the hydrogen bond is towards them.

The CORRECT option is (b) 34

The BEST I can explain: A Chlorine atom is MADE up of 17 electrons. When two Chlorine atoms share an electron covalently, the Chlorine molecule is formed. So the Chlorine molecule Cl2 has a TOTAL of 17 + 17 atoms = 34 atoms.

The CORRECT option is (c) homonuclear diatomic MOLECULES

Explanation: The molecules that have the same atoms in them are called as homonuclear molecules. The molecules that have only two atoms are called diatomic molecules. So H2, N2, O2, and LI2 are called homonuclear diatomic molecules.

The correct choice is (a) Diamagnetic

Easiest explanation: The Nitrogen molecule N2 is diamagnetic in NATURE as it contains zero single electrons, all the electrons are paired. Its bond ORDER is CALCULATED as 3 and the TOTAL number of electrons the nitrogen molecule are 14.

Right answer is (d) 14

For explanation: The ELECTRONIC CONFIGURATION below number of ELECTRONS= 14, i.e. number of electrons = 12 is σ1s^2σ*1s^2σ2s^2 σ*2s^2π2px^2π2y^2but after 14, TAKE number of electrons = 16 is σ1s^2σ*1s^2σ2s^2σ*2s^22pz^2π2px^2π2y^2π*2px^1π*2py^1 So the change COMES near 2pz orbital’s place.

Correct OPTION is (a) True

Best explanation: σ1s^2σ*1s^2σ2s^2σ*2s^22pz^2π2px^2π2y^2π*2px^1π*2py^1 is the electronic CONFIGURATION of O2 molecule. According to this, it has TWO unpaired electrons, making it paramagnetic and is ATTRACTED by the magnetic field.

Right choice is (d) 4, 2

The explanation is: The lithium molecule is denoted by LI2. When the lithium molecule is formed, each of the lithium shares an electron in the 2s ORBITAL. Its ELECTRONIC configuration is σ1s^2σ*1s^2σ2s^2. So the NUMBER of electrons in bonding orbital and anti-bonding orbital of Lithium molecule are 4 and 2respectively.

Right answer is (a) NA = NB

Easiest explanation: When a molecule’s bond order is EQUAL to zero, the molecule cannot exist. The formula for finding out bond order is \(\FRAC{1}{2}\)(NB – NA). So NA – NB = 0, that is NA = NB. Where NA as the number of anti-bonding MOLECULAR orbitals and NB as the number of bonding molecular orbitals.

Correct OPTION is (B) H2

Explanation: The electronic configuration of HE2 is σ1s^2σ*1s^2. Here NA = NB (where NA as the number of anti-bonding molecular orbitals and NB as the number of bonding molecular orbitals). So the molecule He2 doesn’t exist.

The correct option is (a) σ1s^2

Easy explanation: In a hydrogen atom, each hydrogen SHARES an electron from 1S orbital, so in total there are TWO electrons present in 1s bonding orbital of the molecule. So the electronic CONFIGURATION of the hydrogen molecule is σ1s^2.

The correct ANSWER is (d) Repelled by the magnetic field

Best EXPLANATION: Paramagnetic MOLECULES are ATTRACTED by the magnetic field and orbitals are singly occupied. O2 is an example. Whereas DIAMAGNETIC molecules are repelled by the magnetic field, so the option is wrong.

The correct choice is (B) INDIRECTLY proportional

Explanation: The bond LENGTH has defined the distance between TWO atoms in a molecule. The bond ORDER depends on the bond length between two atoms in a molecule. As the bond length increases the bond decreases and vice-versa.

Correct OPTION is (B) 2

The explanation is: The formula of bond ORDER is given by ^1⁄2(NB – NA) When NB is BONDING orbitals and NA is the NUMBER of anti-bonding orbitals. In Oxygen, bond order = 1/2(10-6) = 2. When it’s zero the molecule cannot be formed.

The CORRECT option is (c) is LESS than

For EXPLANATION: When a molecule consists both BONDING MOLECULAR orbitals and anti-bonding molecular orbitals, the higher the number of bonding orbitals, the more the bonding influence and the more stable the molecule will be and vice-versa.

Correct choice is (d) Anti-bonding molecular ORBITAL

The BEST explanation: An ELECTRON that enters bonding ORBITALS stabilizes the MOLECULE as it’ in between two nuclei. Whereas when an electron is entered into the anti-bonding orbital, it needs to pull an electron away from the nucleus.

Correct OPTION is (b) COMBINING ATOMIC orbitals must have symmetry as per molecular AXIS

To elaborate: Combining atomic orbitals must have symmetry as per molecular axis is TRUE. The corrected statements are combining atomic orbitals must have equal energy, must overlap to the maximum extent and Z-axis should be taken as the molecular axis.

The CORRECT option is (a) True

Explanation: The LINEAR combinations LIKE additions and subtractions of wave functions of individual atomic orbitals indicate the formation of molecules MATHEMATICALLY, as given i.e. \(\psi\)MO = \(\psi\)A + \(\psi\)B. Where \(\psi\) represents the wavefunctions of atomic orbitals.

Correct OPTION is (a) one BONDING and one non-bonding orbital

Best explanation: F. Hund and R.F. Mullikan proposed Molecular orbital THEORY in the year 1932. According to this theory, the COMBINATION of two atomic orbitals results in the formation of two molecular orbitals NAMELY one bonding and one non-bonding orbital.

The CORRECT choice is (c) They can form more stable bonds than the pure orbitals

The explanation is: The true statements of the INCORRECT ONES are the number of orbitals FORMED after the hybridization is equal to the number of orbitals before hybridization, the hybrid orbitals have equal energy and the hybridization indicates geometry.

Correct answer is (a) True

Explanation: The hybridization is the INTERMIXING of different ORBITALS in order to form a new set of equivalent orbitals otherwise known as HYBRID orbitals. All the hybrid orbitals those have undergone the same hybridization have the same amount of ENERGY.

Correct answer is (c) s-orbital, p-orbital, and d-orbital

Explanation: Octahedral geometry is POSSIBLE when the atomic ORBITALS under UNDERGOING sp^3d^2 or d^2sp^3 hydration only. So it involves one s-orbital, three p-orbitals, and TWO d-orbitals. An example of this is SF6.

The correct OPTION is (d) 5

The EXPLANATION: The FORMULA of ethene molecule is C2H4. There is one SIGMA bond between two carbon atoms and 2 sigma bonds between each of the carbon and the hydrogens. So in total, it’s five (one pi-bond is present between the 2 carbon atoms).

Correct answer is (B) 109.5°

To EXPLAIN I would say: The molecule of methane i.e. CH4 had undergone sp^3 hybridization (1 s-orbital and 3 p-orbitals COMBINE to give 4 sp^3 orbitals). It exhibits tetrahedral geometry. In tetrahedral geometry, the angle between the BONDS of corner atoms and the central atom is 109.5°.

Correct choice is (b) sp^2

For explanation: In the BCl3 molecule, one s-orbital and two p-orbitals intermix and form three equivalent hybrid ORBITS. Therefore it UNDERGOES sp^2 hybridization and FORMS TRIGONAL planar shape, like B in the center and CL in the 3 corners.

Right option is (d) 50, 50

To ELABORATE: When one s-orbital and p-orbital UNDERGO hybridization, 2 sp orbitals are formed. One sp-orbital has 50% s-character and 50% p-character. They possess LINEAR GEOMETRY and it’s also CALLED diagonal hybridization.

Right OPTION is (a) Pauling

Explanation: In order to explain the bonding and shapes of EVERY polyatomic atomic molecule LIKE METHANE, carbon tetrachloride, water, boron trifluoride, etc, Pauling put-forth the concept of hybridization.

The correct CHOICE is (a) Sigma bond

To explain: The head-on or end to end TYPE of overlapping is PRESENT in sigma bond. A sigma bond is a type of covalent bond. It MAY also be called an axial OVERLAP. In case of the hydrogen molecule, its s-s overlapping.

Right ANSWER is (C) is DEPENDENT on

To explain: As per the concept of valence bond theory, the partial merging of atomic ORBITALS id knowns as overlapping. The extent of overlapping is DIRECTLY proportional to the strength of the covalent bond, i.e. it is dependent.

Correct option is (a) Hydrogen

Easy explanation: The amount of energy that is required to break a chemical BOND in a MOLECULE into INDIVIDUAL atoms is known as bond ENTHALPY. 435.8 kJ mol^-1 is required to DISSOCIATE a hydrogen molecule into two hydrogen atoms.

The correct choice is (b) ClF3 – T-shape

To explain: The molecule ClF5 has T-shape as it 3 bonding pairs and 2 lone pairs, so it’s true. The molecules BrF5, PCl5, and SF4 have the shapes square PYRAMIDAL, trigonal bipyramidal and see-saw respectively.

Right choice is (B) isoelectronic

For explanation: The molecules and IONS that contain the same number of electrons are CALLED isoelectronic SPECIES. They all have the same bond order. For example, the molecules and ions like N2, CO and NO^+ have the bond order 3 and 14 electrons.

Right option is (a) True

Explanation: As the postulate of Valence Shell Electron PAIR Repulsion Theory (VSEPR), a MOLECULE tends to FORM a shape or ORIENTATION that has little repulsion comparatively and the higher distance between the electron PAIRS comparatively.

The correct choice is (a) ionic bond

For EXPLANATION: Ionic bond, which is otherwise KNOWN as electrovalent bond forms between two ATOMS by the transfer of electrons between them. It GENERATES oppositely charged ions. Positively charged ions are mostly METALS and the vice-versa.

Correct OPTION is (d) 0

The best explanation: The formula for finding out the formula charge of an in a molecule = total NUMBER of valence electrons – total number of non-bonding electrons – 1/2(total number of bonding electrons). So here, FORMAL charge of C = 4 – 0 – 8/2 = 0.

Correct option is (c) NaCl

Explanation: The formation of NaCl MOLECULE where Na and Cl transfer electrons to each other forming Na^+ and Cl^–. There is no SHARING of electrons i.e. no COVALENT bond. Whereas the molecules H2O, Cl2 and O2 involve sharing of electrons.

Correct option is (c) degree

The best explanation: The angle between TWO BONDS from the same atom that is bonded to different atoms is called the bond angle. It EXPRESSED in the units of degree EXPERIMENTALLY by spectroscopic methods. It depicts the shape of the molecule in a 3D dimension.