H2SO4 Lewis Structure, Characteristics:51 Complete Quick Facts

This article is regarding the most important acid, H2SO4 lewis structure, and its important facts. Let’s start to discuss it.

H2SO4 lewis structure is often known as Sulfuric acid. It is known as Oil of Vitriol. In most of the reactions in chemistry, we used sulfuric acid as a reagent. The acidity of H2SO4 is very strong. It is an oxoacid of S. the central S is sp³ hybridized. The geometry of the molecule around the central S atoms is tetrahedral. There are two ketonic oxygen and two -OH oxygen groups present.

Sulfuric acid is a good acidic solvent for many organic reactions. Among all the chemicals sulfuric acid is used more. To maintain the acidity of many reactions we used dilute sulfuric acid. Sulfuric acid has a strong affinity toward water molecules.

Some important facts about H2SO4

H2SO4 is a strong mineral acid, it is a colorless, odorless viscous liquid in a physical state. H2SO4 is a strong oxidizing agent and has dehydrated property. The melting point and boiling point of H2SO4 are 283.46 K and 610 K respectively. It is miscible in water and the process is exothermic because some amount of heat is generated.

The vapor pressure of H2SO4 is 0.001mmHg at 20⁰C. the pKa₁ and pKa₂ of H2SO4 are -2.8 and 1.9. so, from the value of pKa, we can say that it is a very strong acid. The viscosity of the acid is 26.7 centipoise (20 °C). The density of H2SO4 is, 1.8302g/cm³. The molecular weight of sulfuric acid is 98.079 g/mol.

Sulfuric acid is prepared mainly through the Contact process. It is a three-step method.

Contact process

In the first step of the contact process, elemental sulfur is burned to produce sulfur dioxide.

S(s) + O₂ → SO₂

In the presence of vanadium pentaoxide(V2O5) oxide as a catalyst, sulfur dioxide is oxidized to sulfur trioxide by oxygen.

2 SO₂ + O₂ ⇌ 2 SO₃

Sulfur trioxide is then absorbed by sulfuric acid by 97-98% and forms oleum (H2S2O7), it is also known as fuming sulfuric acid or pyrosulfuric acid. This oleum is then diluted to get a concentrated form of sulfuric acid.

H2SO4 + SO₃ → H₂S₂O₇

H₂S₂O₇ + H₂O → 2 H2SO4

1. How to draw the H2SO4 lewis structure?

To draw the H2SO4 lewis structure, there are a few many steps we have to follow. Two types of oxygen are bonded to central S atoms, and according to this, we have to draw the H2SO4 lewis structure. After the drawing of the H2SO4 lewis structure, we can predict the different covalent characters and bond properties of H2SO4.

Step 1 – in the first step, we should count the valence electrons for the H2SO4 lewis structure. In the H2SO4 lewis structure, there are three types of atoms S, O, and H present. Now S is the group 16^th element and belongs to the O family, so it has six electrons in the valence shell for S. Now O is also a group VIA element and it has also six electrons in the valence orbital. H is the group IA element and it has only one electron and that one electron can behave as a valence electron.

Now there are one S, four O, and two H atoms present. So, we added the total valence electrons for individual atoms. The total valence electrons for the H2SO4 lewis structure are, [(5*6) +(1*2)] = 32 electrons.

Step 2 – Now we select the central atom for the H2SO4 lewis structure. Based on size and charge, there is confusion between S and O, which can be selected as the central atom. Now the size of S is larger than O, as we know down the group on the same period size of the atom increases, as the principal quantum number increases. So, the size of S is larger than O.

Again, we know that down the group electronegativity decreases. S is placed down the O in group 16^th. So, the electronegativity of S is less than O. So, in the H2SO4 lewis structure S is selected as the central atom.

Step 3 – All the atoms in the H2SO4 lewis structure belong to the s and p block. So, here octet rule applied. According to the octet rule in s block element that the maximum number of an electron can stay in s orbital is two, as s orbital is the valence shell for s block element so, in the valence shell of s block element can complete via accepting one or two-electron. In the p orbital, there is a maximum of six electrons can stay.

So, according to the octet rule in the p block element, they can complete their valence shell with eight electrons, two for the s orbital and six for the p orbital. For the p block element, there must be s orbital will be present.

According to the Octet rule, in the H2SO4 lewis structure, the required number of valence electrons will be, [(2*2)+(5*8)]=44 electrons. But in the H2SO4 the valence electrons are 32. So, the required number of electrons will be 44*32 =12 electrons. These shortages of 12 electrons can be accumulated by a suitable number of bonds. So, the required number of bonds in the H2SO4 lewis structure is 12/2 =6 bonds. So, in the H2SO4 lewis structure, there will be a minimum of six bonds are required.

Step 4 – In this step, we should connect all the atoms in the H2SO4 lewis structure via the required number of bonds. S is placed at the central position. Now there are four O atoms connected to S with four sigma bonds. Only two bonds are remaining and those two bonds are satisfying via two H atoms connected through those two bonds with two O atoms.

Step 5 – In the last step, we should check whether all the atoms are satisfied with the octet rule in the H2SO4 lewis structure. The octet of two H atoms is complete via bonds with two O atoms. Now two O atoms which are making one bond with S and one bond with O are also satisfied with their octet too.

But the octet of S in the H2SO4 lewis structure is not satisfied yet. Those two O atoms only make single bonds with S atoms, their octet is even not completed. Now complete the octet of two O atoms and an S atom, we add a double bond between two O atoms and an S atom. To complete the octet we use multiple bonds and lone pairs in the H2SO4 lewis structure.

2. H2SO4 lewis structure shape

The shape of the H2SO4 lewis structure depends on the electron count for the central atom and also on the hybridization of the central atom. In the H2SO4 lewis structure, the central atom is S and the geometry around the S is tetrahedral. We only count the electron which is involved only in sigma bond formation with the central S atom in the H2SO4 lewis structure.

In the H2SO4 lewis structure, there are four surrounding atoms are present for central S. they contribute one electron and S also contributes one electron for four bonds, so the electrons count will be eight in the central S atom. We should not count the electron of h atoms. Because H atoms are not directly bonded to the central S atom. Although they contribute to valence electrons for H2SO4 lewis structure but not in the shape of the molecule.

According to the VSEPR (Valence Shell Electrons Pairs Repulsion) theory, if the electron count is eight for the central atom then the geometry around the central atom will be tetrahedral. Double bonds required more space so they adopt tetrahedra, if it adopts a square planner structure then, there will be massive bond pair-bond pairs repulsion occur.

3. H2SO4 valence electrons

In the H2SO4 lewis structure, the valence electrons are the sum of individual valence electrons for each atom present. There are three different atoms S, O, and H present. Now we have to calculate the valence electrons for those three toms separately. The environment of two O atoms is different from the other two, so we have to calculate differently the valence electrons for those O atoms.

S is a VIA element, then six electrons are present in its valence shell. H has only one electron and that electron is present as a valence electron for the H atom. Now, O is also VIA group 16^th element. So, it also has six electrons in its outermost orbital. The electronic configuration of S, O, and H are [Ne]3s²3p⁴, [He]2s²2p⁴, 1s¹respectively. So, from the electronic configuration of these three atoms, we know the number of valence electrons for each atom.

There are four O atoms and two h atoms present in the H2SO4 lewis structure. So, the total valence electrons for the H2SO4 lewis structure are, [(2*1) + (4*6) + 6] = 32 electrons. This valence electron in the H2SO4 lewis structure is involved in the formation of the H2SO4 structure.

4. H2SO4 lewis structure lone pairs

In the H2SO4 lewis structure, the lone pairs are available only over O atoms. S and H are contains zero lone pair because all the valence electrons for S are involved in the bond formation and H has only one electron in its valence shell.

In the H2SO4 lewis structure, we count the lone pairs after the successive bond formation of every atom, and how many electrons are present in the valence shell. H has only one electron in its valence shell which is involved in the sigma bond formation with the O atom, so there is no chance for lone pairs over the H atoms.

The electronic configuration of S is [Ne]3s²3p⁴ and we know s is the group 16^th element, so it has six electrons in its valence shell and S makes six bonds in the H2SO4 lewis structure. So, all the valence electrons of S are involved in the bond formation, so there are no available valence electrons for S, so Sulfur also lacks lone pairs in the H2SO4 lewis structure.

Now there are four O atoms in the H2SO4 lewis structure. Two O atoms make sigma two sigma bonds with S and H atoms and another two O atoms make one sigma bond with S and one π bond with S. So, all the four O atoms make two bonds in the H2SO4 lewis structure. Now we know O is group 16^th element so it has sei electrons in its valence shell. O uses two electrons from its valence shell for bond pairs so the remaining four electrons exist as lone pairs for O.

So, the total number of lone pairs available over the H2SO4 lewis structure is 4*2 = 8 pairs of lone pairs.

5. H2SO4 lewis structure formal charge

From the H2SO4 lewis structure, it is evident that there is no charge appearing on the molecule. Now with the help of the formal charge, we should prove that the molecule is neutral or charged. The concept of formal charge is a hypothetical concept accounting for the same electronegativity for all the atoms present in the H2SO4 lewis structure.

The formula we can use to calculate the formal charge, F.C. = N_v – N_l.p. -1/2 N_b.p.

Where N_vis the number of electrons in the valence shell or outermost orbital, N_l.pis the number of electrons in the lone pair, and N_b.p is the total number of electrons that are involved in the bond formation only.

We have to calculate the formal charge separately for S, O, and H atoms.t the environment of O atoms is not the same for all, so we calculate the individually formal charge for O atoms whose environments are the same.

The formal charge over the S atom is, 6-0-(12/2) = 0

The formal charge over the H atom is, 1-0-(2/2) = 0

The formal charge over the O atom is. 6-4-(4/2) = 0

From the formal charge of the H2SO4 lewis structure, we see that there is no charge appearing over the individual atoms. So, the H2SO4 lewis structure is neutral.

6. H2SO4 lewis structure angle

The bond angle of the H2SO4 lewis structure is the bond angle around the central S and surrounding O atoms. The bond angle around the central S is 109.5⁰. the data is given from VSEPR theory as well as hybridization theory.

From the H2SO4 lewis structure, we see that the environment around the central S atom is tetrahedral. From the VSEPR theory, we can say that if a molecule adopts tetrahedral geometry and no lone pairs over the central atom then the bond angle around the central atom is 109.5⁰. which is the ideal bond angle for tetrahedral moiety. The size of S is large enough and it can accumulate four O atoms easily without repulsion. The double-bonded O atoms are far away from the single bond O atoms.

We know double bonds required more space, in tetrahedral moiety, there is enough space that two double-bonded O atoms and two single-bonded O atoms can stay without repulsion. So, in the H2SO4 lewis structure, there is no bond-pair lone pairs repulsion or bond-pair bond pair repulsion. So, the bond angle has not deviated and the value is 109.5⁰.

7. H2SO4 lewis structure octet rule

In the H2SO4 lewis structure, all the atoms are completed their octet via sharing a suitable number of electrons. All the atoms in the H2SO4 lewis structure, are form s and p block elements. For s block, there is a maximum of two electrons that can lie, and s block element complete their octet by two electrons. P block elements can accept a maximum of six electrons and complete their octet via eight electrons as p block contains s orbital.

The central S atom in the H2SO4 lewis structure has six electrons in its outer shell. S is the group 16^th VIA element. S is a p block element so it requires eight electrons to complete its octet. S makes six bonds in the H2SO4 lewis structure, in those six bonds it shares its six electrons and six electrons from the four O sites. So, now it has twelve valence electrons. So, it is a case of violation of the octet rule. S can expand its octet and makes multiple bonds, the size of S is larger is the reason for expanding its octet.

H has only one electron and that electron is the valence electron for H. It is an IA element. Being an s block element H requires two electrons in its valence shell. H shares one electron with O atoms to make sigma bonds. This way H can complete its valence shell and complete its octet.

For the O, it is also a group VIA element like the S atom. It has six electrons in its valence shell. To complete its octet, it required two more electrons because O is a p block element and for a p block element it requires eight electrons to complete the octet.

For double bonded O atoms in the H2SO4 lewis structure, it shares two electrons from itself and two electrons from S, and now it has eight electrons in its valence shell among which four electrons exist as two pairs of lone pairs.

For the single-bonded O atoms, it makes two bonds, one with H and one with S to share its two-electron with them. Now it has two pairs of lone pairs and the rest of the four electrons are the bond pair. This way single-bonded O also completes its octet.

8. H2SO4 lewis structure resonance

In the H2SO4 lewis structure, there are more electron clouds present which can be delocalized over the molecule in different skeleton forms. There is a double bond and electronegative atoms S and O are present and even the counter anion sulfate is more resonance stabilized than the H2SO4 lewis structure.

All three structures are the resonating structure of the H2SO4 lewis structure. Structure III is the most contributing resonating structure of the H2SO4 lewis structure. Because it has a higher number of covalent bonds and there is no charge dispersion over that structure. These two reasons are the stabilization factor. So, it is the more stabilized and contributing structure.

Structure II is less contributing than structure III and more contributing than structure I because it has less number of covalent bonds than structure III but a higher number of covalent bonds than structure I. also it has charge dispersion over the molecule.

Structure I is the least contributing structure, as it contains less number of covalent bonds, and there is also a positive charge over the S atom which is an electronegative atom. There is a double charge present over S. so it has the least contribution in the H2SO4 lewis structure resonance.

So, the order of contributing structure is, III>II>I.

9. H2SO4 hybridization

In the H2SO4 lewis structure, there are different atoms are present with different orbitals, whose energy is different. To make a successive covalent bond they undergo hybridization to form a new equal number of hybrid orbitals of equivalent energy. Here we predict the central atom hybridization of the H2SO4 lewis structure, which is sp³ hybridized.

We used the formula to predict the hybridization of the H2SO4 lewis structure is,

H = 0.5(V+M-C+A), where H= hybridization value, V is the number of valence electrons in the central atom, M = monovalent atoms surrounded, C=no. of cation, A=no. of the anion.

In the H2SO4 lewis structure, the central atom S has six valence electrons and only four electrons are involved in the sigma bond formation and four O atoms are present at the surrounding position.

So, the hybridization of central S in the H2SO4 lewis structure is, ½(4+4+0+) = 4 (sp³)

Structure	Hybridization value	State of hybridization of central atom	Bond angle
Linear	2	sp /sd / pd	180⁰
Planner trigonal	3	sp²	120⁰
Tetrahedral	4	sd³/ sp³	109.5⁰
Trigonal bipyramidal	5	sp³d/dsp³	90⁰ (axial), 120⁰(equatorial)
Octahedral	6	sp³d²/ d²sp³	90⁰
Pentagonal bipyramidal	7	sp³d³/d³sp³	90⁰,72⁰

From the hybridization table we can conclude that if the number of orbital involved in the hybridization is four then the central atom is sp³ hybridized.

Let us understand the mode of hybridization of the H2SO4 lewis structure.

From the box diagram of the H2SO4 lewis structure, it is evident that we only consider the sigma bond. Π bond or multiple bonds are not involved in the hybridization. S has a vacant d orbital so it can expand its octet and form multiple bonds. So, S has not obeyed the octet rule here and this is also proved via the box diagram.

From the hybridization chart, we can see that if the hybridization is sp³ then the predicted bond angle is 109.5⁰. so, here the bond angle for the H2SO4 lewis structure is 109.5⁰. this value of bond angle can be explained via bent’s rule, COSθ =s/s-1, where s is the % of s character in hybridization and θ is the bond angle.

10. H2SO4 solubility

H2SO4 is soluble in the following solvent.

Water
Ethanol
Methanol
benzene

11. Is H2SO4 soluble in water?

Sulfuric acid has a greater affinity toward water molecules. It can soluble in water it is miscible in water. There is a large amount of heat generated when sulfuric acid is dissolved in water. In all concentrations, sulfuric acid can be dissolved in water. The hydration energy of enthalpy for the process of getting dissolved sulfuric acid in water is -814 KJ/mol. The – sign is for the exothermic process because heat is produced in the process.

12. Is H2SO4 polar or nonpolar?

H2SO4 is a very polar molecule. In the H2SO4 lewis structure, there are O and S are mainly present along with H. the electronegativity difference between S and O is enough to make a molecule polar. Again, the shape of the H2SO4 lewis structure is tetrahedral, which is an asymmetric form, and therefore a resultant dipole moment is present in the molecule. So H2SO4 is a polar molecule.

From the diagram, it is evident the direction of dipole moment id from S to O site. O is more electronegative than S, so the flow of dipole moment from S to O occurs. The above geometry is asymmetric, so there is no chance of canceling out any dipole moment the dipole moment value is different for double-bonded and single-bonded O atoms, due to the contribution of S and p orbital. So, in the H2SO4 lewis structure, there is some resultant dipole moment value is present and makes the molecule polar. The molecule is polar again proved by its solubility in a polar molecule like water.

13. Is H2SO4 an electrolyte?

Yes, H2SO4 is an electrolyte, it can soluble in water and makes the aqueous solution ionic.

14. Is H2SO4 a strong electrolyte?

After getting dissolved in water sulfuric acid is ionized into H⁺ ion and HSO4^– very quickly. After over time it can further ionize to form H⁺ and SO4^2-. There is the formation of H⁺ which has greater mobility and for this reason, the whole solution becomes conductive. Sulfuric acid is very quickly ionized in the aqueous solution and makes the whole solution very high conductive of electricity. So, it is a strong electrolyte.

15. Is H2SO4 acidic or basic?

H2SO4 is a pure acidic. It can release an H⁺ ion which makes it acidic. The concentration of H⁺ is very high. When it is dissolved in water the H⁺ is very high making it strong acidic.

As an acid, it can react with many strong bases to form corresponding salt and water molecule.

H2SO4 + Ca(OH)2 = CaSO4 + 2H2O

When reacts with super acid sulfuric acid behaves as a base and is protonated.

[(CH₃)₃SiO]₂SO₂ + 3 HF + SbF₅ → [H₃SO₄]⁺[SbF₆]⁻ + 2 (CH₃)₃SiF

16. Is H2SO4 a strong acid?

The release of H+ ions from sulfuric acid is very easy. The acidity of a molecule depends on the tendency of releasing the H+ ion from it into an aqueous solution. There is electronegative atom O and S present in the H2SO4 lewis structure. The H is bonded with electronegative O atoms, so O is trying to pull the sigma electron density towards itself, so the H-O bond becomes weakening and easily cleaved. So, the releasing of H+ ions from sulfuric acid is a very easy and quick process and for this reason, it is a very strong acid.

17. Is H2SO4 polyprotic acid?

H2SO4 is an example of a polyprotic acid. It is diprotic acid that releases both protons in different pka values. So, the presence of more than one acidic proton is called polyprotic acid.

18. Is H2SO4 diprotic?

There are two acidic protons is present in the H2SO4. These two protons can be donated at suitable pka value. So, it is a diprotic acid.

19. Is H2SO4 dibasic acid?

Yes, H2SO4 is dibasic acid. there are two acidic protons is present in the H2SO4 lewis structure. The pH value of two acidic hydrogens is different, actually in different pka values these two protons can be donated.

The lower the value of pka higher will be the acidity of the proton. So, the first proton is more acidic than the 2nnd proton.

20. Is H2SO4 more acidic than HNO3?

H2SO4 is more acidic than HNO3, as H2SO4 is dibasic acid and the first pka value for H2SO4 is very lower than HNO3.

21. Is H2SO4 more acidic than H3PO4?

Although H3PO4 is tribasic acid, the higher pka value of H2SO4 makes it stronger than H3PO4.

22. Is H2SO4 or H2SO3 a stronger acid?

The conjugate base of H2SO4 is sulfate which is more resonance stabilized than the conjugate base of H2SO3. We know that the higher the stabilization of the conjugate base stronger will be the acidity of the corresponding acid. So, H2SO4 is a stronger acid than H2SO3.

23. Is H2SO4 or HCl a stronger acid?

HCl is stronger than H2SO4. The pka value of HCl is -6.3 which is lesser than H2SO4. We know lesser the value of pka higher will be acidity. So HCl is a stronger acid than H2SO4.

24. Is H2SO4 or H2SeO4 a stronger acid?

H2SO4 is a stronger acid than H2SeO4 because S is more electronegative than Se, so it can pull sigma electron density toward itself more than Se, leading to the cleavage of the O-H bond and releasing of H⁺ being very fast and quick.

25. Is H2SO4 a lewis acid?

S has a vacant d orbital after forming double bonds. So, it can accept lone pairs from suitable lewis base and acts as lewis acid.

26. Is H2SO4 an Arrhenius acid?

According to Arrhenius’s theory, those species are considered acids that can release H⁺ ion aqueous solution. H2SO4 can easily release H⁺ ions in an aqueous solution. So H2SO4 is an Arrhenius acid.

27. Is H2SO4 linear?

No, the geometry of H2SO4 around central S is tetrahedral.

28. Is H2SO4 paramagnetic or diamagnetic?

All the electrons in the H2SO4 are paired form, so H2SO4 is diamagnetic.

29. H2SO4 boiling point

The boiling point of H2SO4 is very high above 300⁰C, for this reason, we use a sulfuric acid bath for crystal melting of any organic molecule.

30. H2SO4 bond angle

The hybridization of the central atom in the H2SO4 lewis structure is sp³ and the shape is tetrahedral, so the O-S-O bond angle is 109.5⁰.

31. Is H2SO4 ionic or covalent?

H2SO4 is a purely covalent molecule, but it shows ionic behavior when it is dissolved in an aqueous solution.

32. Is H2SO4 amphiprotic?

Generally, metal oxides or hydroxides are amphoteric. A metal compound can act as an acid or a base depending on the oxide oxidation state. Sulfuric acid (H2SO4) is acid in water but is amphoteric in superacids, it behaves base then.

33. Is H2SO4 binary or ternary?

H2SO4 is a binary oxoacid of Sulfur.

34. Is H2SO4 balanced?

Yes, the molecular formula of sulfuric acid is purely balanced in the H2SO4 form.

35. Is H2SO4 conductive?

In the aqueous solution, H2SO4 dissociates to form an H⁺ ion and sulfate anion. For these two ions, the aqueous solution becomes conductive.

36. Is H2SO4 a conjugate base?

No, H2SO4 is an acid, the conjugate base of H2SO4 is SO₄^2-. For the stabilization of this conjugate base, the acidity of H2SO4 is so high.

37. Is H2SO4 corrosive?

H2SO4 is very corrosive, it can damage skin, eyes, teeth, and lungs also.

38. Is H2SO4 concentrated?

Generally sulfuric acid is 97-98% pure in form. The concentrated H2SO4 is 36.8 N.

39. Is H2SO4 solid liquid or gas?

In-room temperature H2SO4 is liquid in the state. But the fuming H2SO4 is a gaseous form.

40. Is H2SO4 hygroscopic?

H2SO4 is a highly hygroscopic substance. The dehydrating property of H2SO4 is very high.

41. Is H2SO4 hydrogen bonding?

In the H2SO4 there is no such H bond is present but in the liquid state, there is a chance of intermolecular H bond formation by the lone pairs of O atoms.

42. Is H2SO4 metal or nonmetal?

H2SO4 is a non-metal acid, all the substances present in the H2SO4 are non-metals.

43. Is H2SO4 neutral?

No, H2SO4 is acidic in nature.

44. Is H2SO4 a nucleophile?

H2SO4 acts as a nucleophile in many organic reactions because it has lone pairs which can be donated.

45. Is H2SO4 organic or inorganic?

H2SO4 is an inorganic acid, that’s why it is a very strong acid.

46. Is H2SO4 oxidizing agent?

H2SO4 can act oxidizing agent, it can oxidize several functional groups in organic reactions.

47. Is H2SO4 polyatomic?

Yes, H2SO4 is polyatomic, there are three types of atoms H, S and O are present.

48. Is H2SO4 unstable?

H2SO4 is a very stable molecule unless it gets excited by heat, two double bonds make the molecule very stable.

49. Is H2SO4 volatile?

Yes, H2SO4 is volatile in nature.

50. Is H2SO4 highly viscous?

H2SO4 is highly viscous in a liquid state because there is a large amount of H bonding is observed.

51. Why is dilute H2SO4 used in titration?

Dilute H2SO4 is neither the oxidizing agent nor the reducing agent, so redox titration is ideal.

Conclusion

H2SO4 is a very strong mineral inorganic acid. it is very corrosive to the human being. In many organic transformations, synthesized and maintaining the acidity we can use H2SO4. But there should be kept precautions when it is being used. H2SO4 is the reason for acid rain.

Read more about 11 Facts on H2SO4 + Al(OH)3.

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Biswarup Chandra Dey

Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.