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Questions tagged [ionic-compounds]

Compounds in which at least some of bonds have ionic character stronger than covalent or metallic. Many compounds called salts are ionic compounds but not all of them.

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Ionic equilibrium between multiple ions

This is a question from IIT-JEE 1993: For the reaction $$\ce{[Ag(CN)2]^- -> Ag^+ + 2CN^-}$$ the equilibrium constant at $\pu{298 K}$ is $\pu{4e-10}$. The silver ion concentration in a ...
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Gap in ionic radii

The above picture was shown in a presentation by my prof in inorganic chem as we were discussing ionic radii more in depth (all in pm). These are all isoelectronic radii. Notice the sudden leap in ...
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Calculating the strength of an ionic bond that contains poly-atomic ions

So the bond association enthalpy for ionic compounds like $\ce{NaCl}$ and $\ce{NaBr}$ can be easily calculated from a Born-Haber cycle. But the way a Born-Haber cycle is constructed it uses info that ...
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Ionic compounds and van der Waals forces

I'm having trouble understanding exactly what intermolecular forces occur in ionic compounds. What I understand is that ionic compounds are held together by electrostatic interactions between ...
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What is the reason behind the occurrence of inert electron pair effect?

I was reading the causes of variable electrovalancy and saw that most of the p block elements with configuration ns2 np1-4 have variable valancy and the reason is inert electron pair effect. I ...
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Calling compounds electron deficient [closed]

I believe this is a conceptual question and might sound silly, but please help me with it: I can understand when ions like $\text{Co}^{3+},\text{Mg}^{2+}$ are called electron deficient, because they ...
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Why does Coca-Cola Zero Sugar Contain Sodium Despite no Sodium Ingredients?

According to the Coca-Cola website and every label I read, Coca-Cola Zero Sugar is a mixture of organic compounds: CARBONATED WATER (OC(OH)₂), CARAMEL COLOR (Various sugars), PHOSPHORIC ACID (H₃PO₄...
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Dissociation behaviour of polyelectrolytes

Assuming a solution of 100 polycationic molecules, each of them carrying 100 amino groups and an apparent pKa of 6.5. Would it mean that, at a pH of 6.5, 50 molecules will be fully protonated 50 ...
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will the autoionization of water reduce due to common ion effect? [closed]

When a weak acid is added to water , will the dissociation of water reduce due to common ion effect caused by increased H+ concentration due to acid , my text book said common ion effect is caused by ...
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will two weak acids lower their degree of dissociation when put together in solution compared to when put separately

When two weak acids are put in aqueous solutions separately they will have some value of degree of dissociation, now when both are put together will there be a decrease in their dissociations, I ...
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What drives the formation of salts?

Can someone explain why potassium and chlorine undergo an exothermic reactiom to form an ionic solid despite that potassium has an ionisation energy of 425 kJ mol-1 and chlorine has an electron ...
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Why did we multiply equilibrium constant with concentration of pure water and called it the water product? [duplicate]

Equilibrium constant is calculated by taking active masses of pure liquids as unity. But while calculating ionic product of water we could have simply defined the equilibrium constant as water ...
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Why does covalent nature in ionic solids increase the lattice energy?

I have observed in my textbooks that ionic solid that have a greater covalent character tend to have higher lattice energy. Can this be generalised as fact?
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Wondering about tetrasilicates [closed]

I found two papers from which two different formulae for the tetrasilicate (tetrasilicic acid) are found: 1.https://www.sciencedirect.com/science/article/pii/S0022309302015491. 2.https://www.ncbi.nlm....
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Long linear molecule with alternating elements? [closed]

In the classic freshman physics text Electricity and Magnetism by Purcell, one of his first examples is the computation of the electrical binding energy of a $\ce{NaCl}$ crystal. He models the crystal ...
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Inorganic Chemistry

Which of the following is a covalent bond? 1.Al2O3 2.AlF3 3.AlCl3 4.Al2(SO4)3 The correct answer is AlCl3.But I have a confusion between option c and d.A/c Fajan's ...
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Comparing the Lattice energy of different compounds

I am confused about some concepts related to Lattice energy. First of all,how to compare lattice energy between $2$ compounds belonging to different groups and periods? 1.Between $\ce{AlF3}$ and $\...
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If Mg(OH)2 is insoluble, why does the reaction of MgO and water produce a slightly alkali solution? [closed]

The equation of the reaction is: Mg(OH)2 + H2O -> Mg(OH)2. Why is it that this reaction produces a solution of around pH 9? There are no OH- ions produced.
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Why lattice energy of NaCl is more than CsCl?

Why is the lattice energy of Nacl more than that of CsCl? If size of Na is smaller than that of Cs, then according to Fajan's rule, Na should polarise Chlorine more and therefore, NaCl must have more ...
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How to get ionic radii for coordination number 12?

I am studying $\ce{ABX3}$ perovskites, and I would like to calculate Goldschmidt tolerance factors for them. The $\ce{A}$ sites in these materials have a coordination number $12$. The Shannon's ...
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502 views

How does Borax Solution act as a buffer? [closed]

What type of buffer is it? If it's a Weak Acid-Conjugate Base type of buffer, what is the weak acid and conjugate base?
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Comparing thermal stabilities of MgCl2 and BaCl2

I read that to compare thermal stabilities of ionic solids: if the solid has a monoatomic anion, we compare thermal stability on the basis of lattice energy which is inversely proportional to size. ...
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Finding the error in attempting the equilibrium question through isotherm equations

Consider the partial decomposition of A as: $$\ce{2A(g) <=> 2B(g) + C(g)}$$ At equilibrium $\pu{700 ml}$ of gaseous mixture contains $\pu{100 ml}$ of gas C at $\pu{10 atm}$ and $\pu{...
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Do individual crystals resulting from evaporating a mixture of two ionic compounds contain both cations/anions within the crystal lattice?

I have wondered this for awhile. Let's say I dissolve, without loss of generality, potassium chloride and sodium chloride in water, then evaporate the water. Would any of the resulting crystals ...
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Comparison of Ionic Character

I read somewhere that in d block compounds, higher the oxidation state, higher is the tendency to form covalent bonds. Which also implies that the element will form the most ionic compounds in it's ...
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What is the proof of complete ionic dissociation in water?

Is there any way to prove that ionic compounds, for instance $\ce{NaCl}$, completely dissociate into singular $\ce{Na+}$ and $\ce{Cl-}$ ions within water by hard experimental evidence? Besides ...
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Very elementary question about valence electrons of ionic compound

In a university entrance question, I found this question: What is the number of valence electrons of $\ce{Mg(OH)2}$? Answer = 24 I know that Mg has 2 valence electrons and O has 6. But I don't ...
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Both calcium hydroxide and ethanol have a hydroxide group, then why isn't ethanol ionic?

I am confused on what is a hydroxide exactly is. For example, ethanol has a hydroxide group so does this mean it contains hydroxide ion? Does this make it ionic? I know it is a covalent molecule but ...
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Why do we use different arguments for determining the strength of hydracids and solubility of ionic compounds?

HI is a stronger acid than HF. Why? Because when dissolved in water, the bigger iodide ion handles the negative charge way better than the small fluoride ion. So Iodide ion is a weak conjugate base ...
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Why does the Leidenfrost effect (seemingly) not apply to the case of molten NaCl when it is poured into water?

On pouring molten sodium chloride into water you can see that when molten $\ce{NaCl}$ (table salt, i.e. sodium chloride) is poured into water ($\ce{H2O}$), the Leidenfrost effect appears to be ...
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The Conductivity of Electrolytes based on structure of Ionic Crystal [closed]

Background I want to run an experiment to test the conductivity of various ionic compounds dissolved in water. I was hoping to see some sort of trend in the increase/decrease of conductivity based ...
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Which has a greater dominance: hydration enthalpy or lattice energy?

When I was reading my notes I came up with a problem. I read that for the s block element salts, when checking the solubility, we consider the hydration enthalpy so we decide their stability in water. ...
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How can an ionic bond have partial covalent in character? [duplicate]

I was going through the topic of 'ionic bond' and read this: No bond is 100% ionic in character. It has some percentage of covalent character. I didn't understand how an ionic bond can be ...
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What is the difference between an ionic compound and a salt? [duplicate]

What is the difference between an ionic compound and a salt? They both have a cation and an anion bonded. On one of my homework sheets, it says that $\ce{NaCl}$ is an ionic compound (which it ...
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Ionic liquids and deep eutectic solvent cation vs anion shape

If we consider an ionic liquid of a deep eutectic such as the choline chloride type DESs, why are ionic liquids (and deep eutectics) with not very symmetric cations and very symmetric anions more ...
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Comparing ionic character of group 1 elements

According to Fajan's rule ionic character should increase down the group as the size of cation increase. So it must be $$\ce{LiH < NaH < KH < RbH < CsH}$$ However, the following two ...
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Is a non-compound molecule a chemical substance?

The Wikipedia definition of chemical substance states: A chemical substance, also known as a pure substance, is a form of matter that has constant chemical composition and characteristic properties....
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Metallic character of bonds?

Why in discussions of percent character of bonds, are only ionic and covalent bondings discussed? Do bonds not have a partial metallic character, and are either metallic and ionic-covalent?
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Is PbO ionic compound?

In IIT-JAM 2018, There was one question, which one of the following oxides are ionic? There was one option PbO also. According to the official answer key, PbO isn't ionic. Although I know this ...
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Identifying covalent character in ionic compounds when varying multiple ions

By Fajans' rules, we can easily find out which compound shows covalent character. Example: Among $\ce{NaCl}$, $\ce{MgCl2}$, $\ce{AlCl3}$ which one is more covalent? Answer: There is a point in ...
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Why are ionic reactions very fast in aqueous medium? [closed]

(No, I am not talking about why Ionic Reactions are faster than Covalent reaction.) This question has me stumped. I mean, at first it looks obvious; water is polar in nature, but what exactly does ...
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What changes does zinc chloride undergo when ‘fusing’ on an atomic level? How does this influence reactivity?

I have been using a reaction with an organozincate starting material. This zincate is freshly prepared from zinc chloride and a Grignard reagent. The experimental procedure ‘handed down’ from more ...
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Is it possible to freeze water by dissolving a salt?

Theoretically, by dissolving a salt in water the melting point lowers, approximately 1.86 K kg/mol, making it more difficult to freeze water. However, the process of dissolution of certain salts is ...
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The impossibility of 100% ionic bond

Recently, I read the definition of oxidation state on Wikipedia. It read that a 100% ionic bond is impossible. So what does a 75% ionic and 25% covalent bond mean at all?
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Reversed size dependence in ion solubility

My book says that solubility increases with interionic distance, because the attractive forces between ions gets smaller. However, if one of the ions in a binary ionic system is very large compared to ...
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Are all ionic compounds salts?

According to Wikipedia: A salt is an ionic compound that can be formed by the neutralization reaction of an acid and a base. Are all ionic compounds salts? Are all salts ionic compounds?
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When comparing boiling points of two ionic compounds, what bonding factors should you assess?

When comparing boiling points of two ionic compounds, should you look at their electronegativity difference, lattice energy, or strength from LDF forces (or all 3 factors)? For example, between LiCL ...
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How do you write the ionization equation for calcium hydroxide?

This is a base that would ionize completely, and the dissociation equation would look like this: $$\ce{Ca(OH)2 <--> Ca^2+ + 2OH-}$$ but how would I write the Brønsted equation with water? $$\ce{...
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How do the pKa and pH indicate to the proper environment of protonation?

I have been reading an abstract of a paper for a couple of minutes (reference below) but I cannot understand a piece of it. The abstract: The ionization state and $\mathrm pK_\mathrm a$ of the ...
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Fajans' Rules Versus Lattice Enthalpy

In analyzing the solubility among $\ce{CaF2, CaCl2, CaBr2}$, I found that $\ce{CaF2}$ is insoluble due to high ionization enthalpy. But comparing among $\ce{AgF, AgCl, AgBr }$, it was said that $\...