Re-NEET 2026 | Most Expected Questions of Chemical Bonding By Arjun Sir

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[00:00:41]Students, we are there with you. Please do not lose this opportunity. All the best. Hi students.

[00:00:49]So, we know chemical bonding is an most important chapter for any entrance examination.

[00:00:55]NEET, they're going to ask minimum four to five questions. So, today we'll discuss most important NEET questions from chemical bonding. Also, most expected also you can say. So, then first question if you see if bonded molecule MX3 T-shape, the number of non-bonding pair of electrons.

[00:01:15]So, even this question this time NEET also asked it. So, if you go for T-shape, so whenever T-shape means you can take best example ClF3. So, best example if you take it as here.

[00:01:27]So, this is my ClF3 molecule.

[00:01:31]So, chlorine is a central atom. This is my chlorine. Chlorine has seven electrons on the central atom. Then, you're given molecule as three fluorines. This is fluorine.

[00:01:42]So, again this is fluorine.

[00:01:46]This is fluorine. That means ClF3 molecule has two lone pairs and three bond pairs. It has a T-shape. That means it has two non-bonding electrons. So, non-bonding electrons also you can call two lone pairs. That means my correct option is option B. So, second option you can take. Then if you go for the next question, then if you go for next question, then.

[00:02:10]So, which of the following does not show paramagnetism? I'll give you super trick to answer question based on paramagnetic nature and diamagnetic nature. I repeat, if any molecule, if any molecule, total number of electrons, if any molecule total number of electrons equal to odd number, directly you can go paramagnetic. I repeat again, if any molecule total number of electrons equal to odd number, directly you can go to paramagnetic in nature, or else you can say diamagnetic in nature. If you see NO2, NO2 nitrogen monoxide, this is NCERT in text question, most important.

[00:02:47]NO2 molecule total number of electrons it has odd number of electrons, it is a paramagnetic molecule. How to find?

[00:02:54]Yeah, nitrogen seven atomic number, I have two oxygens, 8 + 8, that means total number of electrons if you see, 15 + 8, it become 23, 23 is odd number.

[00:03:07]Then if you go for NO, 7 + 7 + 8, it equal to 15 electrons, 15 means again odd number, this is paramagnetic. NO special neutral oxide NCERT cover page.

[00:03:20]Then if you go for KO2, KO2 you can call super oxide, a special word. Super oxide has a three electron bond, I repeat again, super oxide special word, it has a three electron bond. So, KO2 super oxide, your total number of electrons again you can count here. Potassium 19, so oxygen 8 + again 8, no doubt it has an odd number. Again you can say paramagnetic nature. Then option D, Na2O, sodium oxide if you see, your sodium electrons 11 + 11 + then if you go for here eight electrons it has no doubt it is an It is not a odd number even number that means no doubt N A O 2 is an diamagnetic molecule. So except N A O 2 rest all are paramagnetic. I repeat again any question based on diamagnetic or paramagnetic directly you can go to if total number of electrons odd number you can say paramagnetic even exception O 2 molecule O 2 molecule is paramagnetic.

[00:04:22]So now in this question right option is fourth option option D you can take.

[00:04:27]Next question if you see Which of the following molecule which does not have two lone pair of electrons? I repeat again which of the following molecule which does not have two lone pair of electrons? Now if you go for valency cell electron pair repulsion theory this is my oxygen here oxygen is my central atom. So oxygen has six electrons in the outermost shell I'm taking six electrons here then I have two fluorines each and every fluorine can form one one bond that means it has in two lone pairs it has in two lone pairs and two bond pairs. So due to presence of two lone pairs and two bond pairs it has an angular shape it has an angular shape. The question what asked does not contain two lone pairs it has two lone pairs. Now second question if you see second option if you see C L F 3 this is my C L F 3 structure chlorine group number seven I have taken seven electrons so this is my fluorine this is my fluorine this is my fluorine no doubt again it has a two lone pairs.

[00:05:30]It has two lone pairs that means this is not correct option. Now if you go for xenon tetrafluoride yes this is my xenon xenon group number eight. So what is the special of xenon? Among the noble gases xenon only reactive. Why is only reactive? Xenon has low ionization potential. Due to presence of low ionization potential, xenon only will form oxides and fluorides. So, this is my xenon, group number eight. I'm taking eight electrons here.

[00:06:01]That means four fluorines given, the formation of bond, formation of bond, formation of bond, formation of bond. Yes, it has again two lone pairs, four bond pairs.

[00:06:12]This is not a correct option. Now, if you go for SF4 SF4 special sulfur belongs to fourth group. This is my sulfur. Sulfur valence electrons if you take six here, that means there is a formation of fluorine, fluorine, fluorine, fluorine bond. Yes, no doubt. SF4 has one lone pair and four bond pairs. It has a seesaw, seesaw sp3d hybridization. It has an sp3d hybridization seesaw. The correct option is option D. So, I repeat again.

[00:06:46]Another extra information for you. SF4 has dipole moment. If any question asked about dipole moment, if any molecule has at least one lone pair at central atom, if any molecule has at least one lone pair at central atom, that molecule has dipole moment, except except xenon tetrafluoride and xenon difluoride. All the molecules having at least one lone pair at central atom, they have a dipole moment. Now, in this question, correct option is SF4. Now, if you go for next question.

[00:07:17]Yes. So, in O2 molecule, yeah, this question is most important. So, in O2 molecule, which of the following molecular orbitals are low in the energy as compared to sigma 2pz orbital? We have a MOT.

[00:07:33]So, MOT proposed by Mulliken. By using Mulliken's MOT, we can find the paramagnetic nature of molecules, we can find the bond order of molecules, we can find the bond length of molecules, we can find the stability of molecules. So, as per this theory, we can find the by using MOT, I'm saying, by using MOT, we can find the magnetic nature of molecules, we can find the bond order of molecules, we can find the bond length of molecules, we can also find the bond energy of molecules. We have a simple relation, we have a simple relation based on this theory, as the bond order increases, bond order increases, bond energy also increases.

[00:08:20]As the bond order increases, stability, S means stability, stability of molecule also increases. As the bond order, as the bond order increases, bond length decreases.

[00:08:35]So, I repeat, as per this theory, if any molecule has bond order equal to zero, if any molecule bond order equal to zero, that molecule does not exist in nature. As per this theory, if you see bond order equal to zero, that molecule does not exist. Best example, four electron, four For example, you can take four electrons like a He2 molecule, then eight electrons, eight electrons like a B2 molecule, 20 electrons like a Ne2 molecule does not exist. These molecules are does not exist as per this theory. I repeat again. So, by using MOT, we can find the bond order, we can find the paramagnetic nature, we can find the bond length, we can find the whether molecule exist or not. So, I repeat, as per this theory, molecules having four electrons, eight electrons, 20 electrons does not exist.

[00:09:33]So, now if you go for given question, just we can go for Millikan second rule. Just we have a formula sigma 1s2.

[00:09:42]While writing electronic configuration, sigma star 1s2, sigma 2s2, sigma star 2s2. Then you can take it as a rule.

[00:09:57]Sigma 2p z sigma 2p z. Then you can take pi 2px equal to pi 2py.

[00:10:09]Two electrons, two electrons, two electrons.

[00:10:12]Then you can take pi 2px star equal to pi 2py star. It has one electron, one electron. This is the electronic configuration of O2 molecule. In the given question, if you see she asked me what she the energy lower energy than sigma 2pz orbital.

[00:10:38]That means if you see, no doubt at all, sigma 2pz orbital here. This is my sigma 2pz orbital. So as compared to sigma 2pz orbital, these orbitals have low amount of energy. So that means what? It can be sigma 1s, so it can be what? Sigma 2s, and also what? It can be sigma star 2s.

[00:10:58]That means my correct option is you can take it as a 213. You can take 213 is the correct option.

[00:11:06]213 you can take correct option.

[00:11:10]So I repeat again, if any molecule, any molecule has total number of electrons odd number, you can call again paramagnetic except O2 molecule. So if total number of electrons even number, you can call diamagnetic.

[00:11:25]So then if you go for the next question, the number of water molecules directly attached to one water molecule is Yes, this question most important. So, in your chemical bonding chapter, if you see, this is based on hydrogen bonding. So, what is mean by hydrogen bonding? Simple trick to identify hydrogen bonding. If any molecule has OH bond or NH bond or FH bond, that type of bonding you can call hydrogen bonding. Hydrogen bonding means only these three in the syllabus.

[00:11:59]So, due to presence of hydrogen bonding, molecules will show abnormal boiling point. So, due to presence of hydrogen bonding, boiling point increases. So, no doubt water has an hydrogen bonding. In the liquid state, 1 mole of water molecule, the liquid state, 1 mole of water molecule surrounded by 4 moles of water molecules. So, due to formation of intermolecular hydrogen bonding. Due to formation of extensive hydrogen bonding. That means, if you see, 1 mole of water molecule is directly surrounded by 4 moles of water.

[00:12:52]So, correct option should be option D.

[00:12:54]Option D is the correct option. So, I repeat again, in liquid state, 1 mole of water molecule is surrounded by 4 moles of water molecules. Correct option is fourth option. That means, four you can take. So, next question if you move, the number of So, next question if you see, the bond angle in PH3 molecule. So, this question from 50A group elements. So, in 50A group elements, no doubt in 50A group elements or 60A group elements or 70A group elements, top to down in hydrides in hydrides top to down if you go for top to bottom, so bond angle decreases.

[00:13:34]So bond angle decreases. No doubt ammonia as ammonia has high bond angle 107. So as compared to ammonia, PH3 molecule has low bond angle. That means correct option should be a bond angle of PH3 molecule is lesser than ammonia. Lesser than ammonia.

[00:13:54]So correct option should be I'll give you one trick to remember here. Also questions based on here they're asking boiling point of hydrides. So I'll give you super trick to find answers. Just remember trick B snap. B snap is a trick to find B snap.

[00:14:11]So B snap is a trick to answer question based on boiling point of hydrides. So what is mean by B snap? How to apply?

[00:14:19]Yes, B snap means B means bismuth hydride.

[00:14:23]Bismuth hydride. S means antimony hydride.

[00:14:28]N means ammonium.

[00:14:31]Ammonia. S means arsenic hydride.

[00:14:35]P means phosphine. So this is a trick to remember boiling point of hydrides from fifth group hydrides. Maybe this question they can ask NCERT in-text question most important. So B snap B snap trick to answer boiling point of fifth A group hydrides.

[00:14:52]Now if you go for next question.

[00:14:56]Yes, the correct order of dipole moment of hydrogen fluoride, H2S, and water molecule. No doubt. What is mean by dipole moment? So by using dipole moment you can differentiate whether molecule is polar or nonpolar. So if any molecule if any molecule has polar nature, that means any molecule has dipole moment, that molecule you can say polar covalent compound. So if any molecule dipole moment zero, that molecule you can say covalent compound.

[00:15:26]So, what is mean by dipole moment?

[00:15:29]The product of magnitude of charge, the product of magnitude of charge and the distance between two ions. The product of magnitude of charge and the distance between two ions in a covalent molecules, we can say dipole moment. So, I repeat again. Dipole moment depends upon electronegativity and bond length.

[00:15:50]More is the electronegativity, more is the electronegativity, more is the dipole moment. More is the bond length.

[00:15:57]Generally, as the bond length increase, dipole moment increase, but all not always. It is also depends upon electronegativity. So, generally here if you see, water water is a polar molecule, no doubt at all. Then HF also polar molecule, no doubt.

[00:16:12]Even H2S also you can say polar molecule, no doubt. But here as compared to as compared to HF, water has high dipole moment. The dipole moment of water molecule is 1.85 1.85 D.

[00:16:29]The dipole moment of HF molecule is 1.1.82 D. That means as compared to hydrogen fluoride, as compared to hydrogen fluoride, water has high dipole moment.

[00:16:41]Even some books given HF has high dipole moment, but the dipole moment of HF changes. But if you see, water correct option is water has the high dipole moment then see water has high dipole moment then if you go for see this is correct option here. So, number one is water. You can go with this option.

[00:16:59]Generally, here given option if you see I repeat, number one is water you can take. Number two you can take H2S gas.

[00:17:07]Number Sorry. Number HF you can take.

[00:17:11]HF you can take. Least you can take it as a H2S. But some books given some books also given HF as more, but you can is the correct option. So you can go with water, HF, H2S.

[00:17:24]So next question if you see.

[00:17:28]Yes.

[00:17:30]If two atoms, if two atomic orbitals combine, the energy of bonding orbital is lower by X, while that anti-bonding orbital, I repeat again, this question based on VBT, valency bond theory. So valency bond theory If you go for valency bond theory, valency bond theory tells us, okay?

[00:17:51]Valency or everybody tells us formation of bonding only. Always remember, bonding orbital, bonding orbitals, bonding orbitals are more stable than anti-bonding orbital. That means energy point of view. So anti-bonding orbitals have high amount of energy. Bonding orbitals have low amount of energy. That means if you see here, X is generally the bonding orbital lower by yes, correct number. Correct if you see, that means here anti-bonding Y. That means energy point of view, Y has maximum energy than X.

[00:18:27]So as per energy, anti-bonding orbital has high amount of energy than bonding.

[00:18:33]As per stability, bonding orbitals are more stable than anti-bonding.

[00:18:39]So correct option if it should be Y greater than X. Second option you can take.

[00:18:48]Then if you go for next question. In the formation of I3- as another most important question, another most important question, in the formation of I3- Lewis base is So then if you go for I3-, the formation of I3- it is in the I2 plus I- combines to form I3-, I3-. So then if you see here I minus act as a I minus act as a Lewis base. So, correct option is option D, I minus.

[00:19:19]Even after formation of I3 minus, it can dissolve in water. I repeat, before I2 insoluble in water. I2 insoluble in water. After adding I minus, it become polar, it can dissolve in water. This question is most important.