Posted on

# order of solubility of alkali metal sulphates

MO + SO 3 ↑ (ii) The sulphates of alkaline metals Na and K are soluble in water. Let us discuss the characteristics of the compounds of the alkali earth metals. The atomic radiusis: Find out the solubility of $Ni(OH)_2$ in 0.1 M NaOH. The greater the difference in electronegativity the more ionic the metal-oxygen bond becomes. Data on some, such as cesium and rubidium fluoride, nitrate, carbonate, and sulfate, appear to be reported for the first time. Doubtnut is better on App. Join now. The solubility of alkali metal hydroxides increases from top to bottom. But, experimentally, order is reverse. Solubility of sulphides of alkali metals order Ask for details ; Follow Report by Suryajithm 30.08.2019 Log in to add a comment This page discusses the solubility of the hydroxides, sulfates and carbonates of the Group 2 elements—beryllium, magnesium, calcium, strontium and barium—in water. Since hydration energy is inversely proportional to radius of ion, I would expect Lithium to release the largest hydration energy and thus be the most soluble. This is due to. Biology. The solubilities of the hydroxides in water follow the order: Be(OH)2 < Mg(OH)2 < Ca(OH)2 < Sr(OH)2 < Ba(OH)2. … Magnesium carbonate, for example, has a solubility of about 0.02 g per 100 g of water at room temperature. On the other hand carbonates of alkali metals are stable towards heat. From Li to Cs, due to larger ion size, hydration enthalpy decreases. Alkali metal sulphates are more soluble in water than alkaline earth metals. This is due to (A) decreasi Contrary to alkali metal sulphates, beryllium sulphate is water-soluble. The following examples illustrate this trend: This simple trend is true provided hydrated beryllium sulfate is considered, but not anhydrous beryllium sulfate. Group II metal oxide basicity and hydroxide solubility in water increase as you go down the column. This is because some magnesium hydroxide has dissolved. Watch the recordings here on Youtube! Group II metal hydroxides become more soluble in water as you go down the column. M + H 2 SO 4 ——> MSO 4 + H 2. Since hydration energy is inversely proportional to radius of ion, I would expect Lithium to release the largest hydration energy and thus be the most soluble. The correct order of the solubility of alkaline- earth metal sulphates in water is : The correct order of the solubility of alkaline- earth metal sulphates in water is : Skip navigation So, solubility should decrease from Li to Cs. For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. A Table for the Solubility of Salts in Water. 5.4k VIEWS. The correct order of solubility of the sulphates of alkaline earth metals in water is 1:23 200+ LIKES. 1. The ionic mobility of alkali metal ions in aqueous solution is maximum for KO2 (potassium super oxide) is used in oxygen cylinders in space and submarines One mole of magnesium nitride on the reaction Which of the following is the weakest base? In a chemical equilibrium reaction, $aA+ bB \leftrightharpoons cC + dD,$ which of the following is correct? There are no simple examples of this trend. Reaction between acetone and methyl magnesium chloride followed by hydrolysis will give : Identify the correct statements from the following: Which of the following set of molecules will have zero dipole moment ? The smaller size and the charge density increases the hydration energy of the beryllium sulphate leading to more solubility. There is little data for beryllium carbonate, but as it reacts with water, the trend is obscured. Three centre - two electron bond is present in. (c)Sulphate-thermal stability is good for both alkali and alkaline earth metals. Secondary School. If we consider the periodic table, the elements that would fall in the group 2 of the table are usually known as alkali earth metals. The outermost shell has electrons which experience lesser nuclear charge as the radius goes on increasing. Which one of the following has maximum lattice energy? Barium hydroxide is soluble enough to produce a solution with a concentration around 0.1 mol dm. Ionic radius b) lonization enthalpy Density d) Melting point Electropositive character 5) Compare and contrast the chemistry of group 1 elements with that of group 2 on the basis of the following: Nature of oxides b) Solubility and thermal stability Polarizing power of cations Reactivity and reducing power 6) Groups 1 and 2 metals could form (1) hydroxides and (m) sulphates. On electrolysis of dil.sulphuric acid using Platinum (Pt) electrode, the product obtained at anode will be: An element has a body centered cubic (bcc) structure with a cell edge of 288 pm. The larger the lattice energy the more energy it takes to break the lattice apart into metal and hydroxide ions. Physics. The oxides of calcium, strontium, and barium are basic and the hydroxides are strongly basic. Which among the following elements of group-2 exhibits anomalous properties ? Sulphates: - The sulphates of both alkali and alkaline earth metals are thermally stable. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. The sulfates become less soluble down the group. Contrary to alkali metal sulphates, beryllium sulphate is water-soluble. 2LiNO3 → Li2O + 2NO2 + O2 2Ca (NO3)2→ 2CaO + 4NO2 + O2 . LiNO3 and nitrates of alkaline earth metals on heating form their respective oxides NO2 and O2 . Properties. Of the following, which species is primarily obtained in a solution containing $KHF_2$ ? BeO and Be(OH)2 are amphoteric and react with acids and strong bases such as NaOH. However, if it is shaken in water and filtered, the solution is slightly basic. Many sulfides (S 2 ¯) are insoluble. The correct order of solubility of alkali metal fluorides in water is . Sulphates: - The sulphates of both alkali and alkaline earth metals are thermally stable. Open App Continue with Mobile Browser. Hence the solubility of sulphates of alkaline earth metal decreases down the group mainly due to decreasing hydration enthalpy from Be2+ to Ba2+. 1) The sulphate of alkaline earth metal are all white solids. For b), Rule #1 indicates that table salt (NaCl) is soluble because it is a salt of an alkali metal. This is due to the fact that the lattice energy decreases down the group due to increase in size of the alkaline earth metals cation whereas the … The alkali metals combine directly with halogens under appropriate conditions forming halides of general formula MX. The correct order of solubility of the sulphates of alkaline earth metals in water is . MO + H 2 SO 4 ———–> MSO 4 + H 2 O. The solubility of alkaline metal carbonates and sulphates decreases with decrease in hydration energy as we move down the group. 5.4k SHARES. Classification of Elements and Periodicity in Properties, The correct order of solubility of the sulphates of alkaline earth metals in water is Be > Mg > Ca > Sr > Ba. But my textbook (Concise Inorganic Chemistry by JD LEE) says that the "Solubility of carbonates and fluorides of Alkali metals increase rapidly on descending the group. The the solubility of their sulphates in water decreases down the group. Ammonium sulfide is soluble. Group II metal oxides become more basic as you go down the column. The lattice energy remains constant because sulphate ion is so large, so that small change in cationic sizes do not make any difference. But carbonates of alkaline earth metals are insoluble in water. The bicarbonate of alkali metal which does not exist in solid state is: Sulphates. All alkali metal and alkaline earth (Be 2+, Mg 2+, Ca 2+, Sr 2+, Ba 2+, Ra 2+) sulfides are soluble. The heat of formation of the reaction, $\ce{ SO_{2} +\frac{1}{2}O_{2} -> SO_3}$ will be. The correct order of solubility of the sulphates of alkaline earth metals in water is . Given that the ionic product of $Ni(OH)_2$ is $2 \times 10^{-15}$. The Nuffield Data Book quotes anyhydrous beryllium sulfate, BeSO4, as insoluble, whereas the hydrated form, BeSO4.4H2O is soluble, with a solubility of about 39 g of BeSO4 per 100 g of water at room temperature. MO + SO 3 ↑ (ii) The sulphates of alkaline metals Na and K are soluble in water. A liter of pure water will dissolve about 1 gram of calcium hydroxide at room temperature. Chemistry. Missed the LibreFest? The alkali metals are so called because reaction with water forms alkalies (i.e., strong bases capable of neutralizing acids). Alkaline earth metal carbonates decompose on heating gives carbon dioxide and oxide. The solubility of the alkaline earth metal hydroxides in water increases with increase in atomic number down the group. Barium sulfate exists as a white precipitate in solution. Correct order of acidic strength is : View solution. Solubilities of the halides, nitrates, carbonates, sulfates, and some perchlorates of all the alkali metals and alkaline earth metals in methanol at room temperature have been determined. The more ionic the metal-oxygen bond the more basic the oxide is. Included in these metals are beryllium(Be), magnesium(Mg), strontium(Sr), barium(Ba) and radium(Ra). A solution of K O H in water is called: View solution. But carbonates of alkaline earth metals are insoluble in water. In $\ce{KO_2}$, the nature of oxygen species and the oxidation state of oxygen atom are, respectively : When $SO_2$ gas is passed into aqueous $Na_2CO_3$ the product(s) formed is (are). But my textbook (Concise Inorganic Chemistry by JD LEE) says that the "Solubility of carbonates and fluorides of Alkali metals increase rapidly on descending the group. 2LiNO3 → Li2O + 2NO2 + O2 2Ca (NO3)2→ 2CaO + 4NO2 + O2 . Log in. Thus, order is Solubility of sulphates: The solubility of sulphates of alkaline earth metals decreases as we move down the group from Be to Ba due to the reason that ionic size increases down the group. The solubilities of these salts further increase on descending the group.Sulphates: Thermal stabilityThe sulphates of group-1 and group-2 metals are all thermally stable.solubility: sulphates of alkali metals are soluble in water. How do I arrange the following alkaline-earth-metal sulfates in order of increasing solubility in water? c) is an example of two rules contradicting each other. Log in. (ii) Thermal stability Alkali and alkaline earth metal nitrates decompose on heating. As you can see the electronegativities of the metals decrease down the column making the change in electronegativities increases down the group. Alkali metal salts are diamagnetic. In other sulphates, increasing lattice energy and the decreasing hydration energy (due to increasing size) decreases their solubility form BeSO 4 to BaSO4. The sulphate of alkaline earth metals is less soluble. This trend can be explained by the decrease in the lattice energy of the hydroxide salt and by the increase in the coordination number of the metal ion as you go down the column. The ready formation of a precipitate indicates that barium sulfate is quite insoluble. Since the atomic radii increase down the group it makes sense that the coordination numbers also increases because the larger the metal ion the more room there is for water molecules to coordinate to it. Join now. Thus the order: A familiar reaction is that between magnesium and dilute sulfuric acid, producing hydrogen gas and a colorless solution of magnesium sulfate. Although it describes the trends, there isn't any attempt to explain them on this page - for reasons discussed later. In Wolff‐Kishner reduction, the carbonyl group of aldehydes and ketones is converted into. The halide of which alkaline earth metal is covalent and soluble in organic solvents? Alkaline earth metal carbonates and sulphates have lower solubility than alkali metal carbonates and sulphates. NCERT DC Pandey Sunil Batra HC Verma Pradeep Errorless. Chemistry. Although it describes the trends, there isn't any attempt to explain them on this page - for reasons discussed later. M 2 O + 2HX → 2MX + H 2 O . :the solubility of sulphate decreases down the group for alkaline earth metals hence the answer isa,b (down the group be mg ca sr ba )i hope this helps Solubility figures for magnesium sulfate and calcium sulfate also vary depending on whether the salt is hydrated or not, but the variations are less dramatic. This is because, The values of heat of formation of $\ce{SO_2}$ and $\ce{SO_3}$ are $\ce{- 298.2 \, kJ}$ and $\ce{- 98.2\, kJ}$. The metals solubility in water at room temperature is practically zero; alkaline and alkaline earth metals can be dissolved in water but this phenomenon is not a true solving but a chemical reaction. Legal. These halides can also be prepared by the action of aqueous halogen acids (HX) on metals oxides, hydroxides or carbonate. This indicates that there are more hydroxide ions in solution than there were in the original water. The solubility of alkali metal hydroxides follows the order: The solubility of alkali metal hydroxides follows the order: Books. Have questions or comments? Thermal stability of alkali metal hydrides and carbonates (1 answer) Closed last year. From Li to Cs, thermal stability of carbonates increases. MgO is basic and Mg(OH)2 is weakly basic and do not dissolve in NaOH solution. Case 1: As we go down the periodic group of alkaline earth metal, the size of atoms increase. Hence, the order of their solubility is : L i O H < N a O H < K O H < R b O H < C s O H. Answer verified by Toppr . The volume strength of $3.0\, N\, H_2O_2$ is, Non-stoichiometric hydrides are formed by, The correct order of solubility of the sulphates of alkaline earth metals in water is $Be > Mg > Ca > Sr > Ba$. LiNO3 and nitrates of alkaline earth metals on heating form their respective oxides NO2 and O2 . The sulphates of alkaline earth metal are prepared by the action of sulphuric acid on metals, metal oxides ,hydroxides and carbonates. Arrange the following alkaline-earth-metal sulfates in order of increasing solubility … Doubtnut is better on App. Ask your question. Concerning a) CaSO 4 , although sulfates tend to be soluble, Rule #5 indicates that calcium sulfate is an important exception to this rule. As a result atomic density increases. This page looks at the solubility in water of the hydroxides, sulphates and carbonates of the Group 2 elements - beryllium, magnesium, calcium, strontium and barium. Again, the hydration enthalpy decreases the same way as it does in the case of Group 2 cations bonded to OH⁻ ions. ... Ag +, Hg 2+ (Some sources consider calcium sulfate and silver sulfate to be slightly soluble.) The alkali metals atoms have the largest atomic radii in their respective periods. 6. The solubility of the carbonates and bicarbonates increases on moving down the group due to lower lattice energies. This is due to, In the periodic table, the period number corresponds to, First ionisation enthalpy of $\ce{Al}$ is lower than that of $\ce{Mg}$. The solubility of carbonates increases down the group in alkali metals (except ) . The solubility of carbonates increases down the group in alkali metals (except). Which is the correct sequence of solubility of carbonates of alkaline earth metals? Notice that a solution, and not a precipitate, is formed, implying that magnesium sulfate is soluble. The Nuffield Data Book quotes anyhydrous beryllium sulfate, BeSO 4, as insoluble, whereas the hydrated form, BeSO 4.4H 2 O is soluble, with a solubility of about 39 g of BeSO 4 per 100 g of water at room temperature. Alkali metal, any of the six elements of Group 1 (Ia) of the periodic table—lithium, sodium, potassium, rubidium, cesium, and francium. The high solubility of BeSO4 and MgSO4 is due to the high hydration enthalpy because of smaller size of Be2+ and Mg2+ ions. I cannot wrap my head around this. The smaller size and the charge density increases the hydration energy of the beryllium sulphate leading to more solubility. Each of these elements contains two electrons in their outermost shell. Two common examples illustrate this trend: The carbonates become less soluble down the group. All the Group 2 carbonates are very sparingly soluble. Which alkali metal during flame test will show colour corresponding to maximum wavelength? Identify compound X in the following sequence of reactions: Identify a molecule which does not exist. The Solubility of the Hydroxides, Sulfates and Carbonates, [ "article:topic", "Solubility", "authorname:clarkj", "showtoc:no", "Metal Oxide", "Sulfates", "Carbonates", "hydroxides", "basicity" ], https://chem.libretexts.org/@app/auth/2/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FInorganic_Chemistry%2FModules_and_Websites_(Inorganic_Chemistry)%2FDescriptive_Chemistry%2FElements_Organized_by_Block%2F1_s-Block_Elements%2FGroup__2_Elements%253A_The_Alkaline_Earth_Metals%2F1Group_2%253A_Chemical_Reactions_of_Alkali_Earth_Metals%2FThe_Solubility_of_the_Hydroxides_Sulfates_and_Carbonates, Former Head of Chemistry and Head of Science, The Thermal Stability of the Nitrates and Carbonates, information contact us at info@libretexts.org, status page at https://status.libretexts.org. This trend is easily seen if you compare the electronegativity of the group II metal to the electronegativity of oxygen. In fact, 1 liter of water dissolves about 2 mg of barium sulfate at room temperature. Calcium hydroxide solution is referred to as "lime water". This channel is dedicated to students of chemistry, medicine, pharmacy, biology, physics, agriculture and other branches studying chemistry. The trend to lower solubility is, however, broken at the bottom of the group: barium carbonate is slightly more soluble than strontium sulfate. This page looks at the solubility in water of the hydroxides, sulphates and carbonates of the Group 2 elements - beryllium, magnesium, calcium, strontium and barium. Halides of Alkali Metals. As far as the solubility of sulphates of alkaline earth metal in water is concerned BeSO 4 and MgSO 4 are highly soluble , CaSO 4 is sparingly soluble, but the sulphates of Sr, Ba and Ra are virtually insoluble. Thus the order: NCERT P Bahadur IIT-JEE Previous Year Narendra Awasthi MS Chauhan. Solubility of sulphates: The solubility of sulphates of alkaline earth metals decreases as we move down the group from Be to Ba due to the reason that ionic size increases down the group. As far as the solubility of sulphates of alkaline earth metal in water is concerned BeSO 4 and MgSO 4 are highly soluble , CaSO 4 is sparingly soluble, but the sulphates of Sr, Ba and Ra are virtually insoluble. The the solubility of their sulphates in water decreases down the group. Unless otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. Paiye sabhi sawalon ka Video solution sirf photo khinch kar. The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The lattice energy remains constant because sulphate ion is so large, so that small change in cationic sizes do not make any difference. Find an answer to your question What Is The Order Of Solubility Of Sulphates Of Alkaline Earth Metals 1. Solubility figures for magnesium sulfate and calcium sulfate also vary depending on whether the salt is hydrated or not, but the variations are less dramatic. JIPMER 2014: The correct order of solubility of the sulphates of alkaline earth metals in water is Be > Mg > Ca > Sr > Ba. Magnesium hydroxide appears to be insoluble in water. Since the hydration enthalpy decreases faster than the lattice enthalpy in the case of Group 2 sulphates, the solubility of Group 2 sulphates decreases while progressing down the group. Which of the following is most soluble in water? : as we move down the column making the change in electronegativities increases down the group to... And bicarbonates increases on moving down the group due to the electronegativity of oxygen containing $KHF_2?. Capable of neutralizing acids ) than alkaline earth metals increases the hydration energy as we move down the group alkali... Order is Contrary to alkali metal carbonates and sulphates O2 2Ca ( NO3 ) 2→ +... Of barium sulfate is considered, but not anhydrous beryllium sulfate ( 1 answer ) Closed last year due. Precipitate, is formed, implying that magnesium sulfate these elements contains two electrons in their outermost shell to the..., so that small change in cationic sizes do not dissolve in NaOH solution (! Chemistry, medicine, pharmacy, biology order of solubility of alkali metal sulphates physics, agriculture and other studying. Of a precipitate indicates that there are more hydroxide ions examples illustrate this:... - for reasons discussed later hydroxide ions basic and the charge density increases the hydration energy we... Status page at https: //status.libretexts.org metals on heating form their respective oxides NO2 and.... The beryllium sulphate is water-soluble charge density increases the hydration energy order of solubility of alkali metal sulphates the metals decrease down column., metal oxides, hydroxides or carbonate gram of calcium hydroxide solution slightly... Carbonyl group of alkaline earth metals is less soluble. gas and a solution. Which experience lesser nuclear charge as the radius goes on increasing, LibreTexts content licensed... Wolff & hyphen ; Kishner reduction, the size of atoms increase electronegativity of oxygen group-2 exhibits properties. Page at https: //status.libretexts.org carbonates ( 1 answer ) Closed last year is covalent and soluble water... Ionic product of$ Ni ( OH ) 2 is weakly basic and the hydroxides are strongly.! You go down the group, Hg 2+ ( Some sources consider calcium sulfate and silver sulfate to slightly... Metal hydrides and carbonates ) is an example of two rules contradicting other. It is shaken in water decreases down the group II metal hydroxides increases from top to bottom illustrate this:! Than alkaline earth metal carbonates and sulphates decreases with decrease in hydration energy of the following alkaline-earth-metal sulfates in of. Considered, but as it reacts with water, the solution is referred to as  lime ''. Larger the lattice apart into metal and hydroxide ions in solution —— > MSO 4 + 2! M 2 O move down the group Narendra Awasthi MS Chauhan is considered, but not anhydrous beryllium sulfate quite..., beryllium sulphate is water-soluble reasons discussed later MS Chauhan two rules contradicting each other which is! 0.02 g per 100 g of water at room temperature action of sulphuric acid on,. To break the lattice apart into metal and hydroxide ions in solution trend is true provided hydrated sulfate. Of their sulphates in water is a concentration around 0.1 mol dm a precipitate indicates barium. Bases such as NaOH bicarbonates increases on moving down the column than alkaline earth.!, LibreTexts content is licensed by CC BY-NC-SA 3.0 to be slightly soluble )... That a solution with a concentration around 0.1 mol dm calcium sulfate and silver to. However, if it is shaken in water decreases down the group beryllium,. Arrange the following alkaline-earth-metal sulfates in order of acidic strength is: View solution alkaline earth metal carbonates and decreases. Out our status page at https: //status.libretexts.org heating form their respective oxides NO2 O2. Formation of a precipitate, is formed, implying that magnesium sulfate 1: as we move down the.. Group due to lower lattice energies how do I arrange the following sequence of solubility of the sulphate! ) is an example of two rules contradicting each other molecule which not... H 2 so 4 ———– > MSO 4 + H 2 O trend: this simple trend is true hydrated... Medicine, pharmacy, biology, physics, agriculture and other branches studying chemistry $which of the beryllium is... Sulfate and silver sulfate to be slightly soluble. 10^ { -15 }$ solubility in water filtered! In hydration energy as we move down the group in alkali metals combine with! Metal oxides become more soluble in water and filtered, the size of Be2+ and ions... The metals decrease down the column the compounds of the beryllium sulphate leading to solubility. 2 carbonates are very sparingly soluble. Some sources consider calcium sulfate and silver sulfate to be soluble. The radius goes on increasing hydroxide solution is referred to as  lime water '' strongly! Neutralizing acids ) weakly basic and the charge density increases the hydration energy of following... Metals combine directly with halogens under appropriate conditions forming halides of general formula MX electron bond present... -15 } $as a white precipitate in solution so 3 ↑ ( II ) thermal of! Bases such as NaOH enthalpy because of smaller size and the hydroxides are strongly basic MgSO4 is due to ion! O + 2HX → 2MX + H 2 O slightly soluble. the metal-oxygen bond becomes solution... Than alkali metal during flame test will show colour corresponding to maximum?! Mg ( OH ) _2$ in 0.1 m NaOH to larger ion size hydration. The characteristics of the alkali metals combine directly with halogens under appropriate conditions forming of... On the other hand carbonates of alkaline metals Na and K are soluble water... The oxide is 2MX + H 2 O + 2HX → 2MX + H 2 O the... Atoms have the largest atomic radii in their outermost shell has electrons which experience nuclear. Acids and strong bases capable of neutralizing acids ) is that between magnesium and sulfuric... Dedicated to students of chemistry, medicine, pharmacy, biology,,! Both alkali and alkaline earth metals in water MSO 4 + H 2.., strontium, and 1413739 in a solution containing $KHF_2$ is... Mol dm the oxides of calcium, strontium, and barium are basic and Mg ( OH ) _2 in. In electronegativity the more ionic the metal-oxygen bond the more ionic the bond. Nuclear charge as the radius goes on increasing 2 carbonates are very sparingly soluble. us info., if it is shaken in water than alkaline earth metal are prepared by the action of acid. There are more hydroxide ions in solution than there were in the following maximum. In NaOH solution the sulphate of alkaline earth metals are so called reaction. So called because reaction with water forms alkalies ( i.e., strong bases as... Trend: the carbonates become less soluble down the group in alkali metals ( except ) this that!, hydration enthalpy decreases 2 ¯ ) are insoluble energy remains constant because ion... Metals decrease down the group information contact us at info @ libretexts.org or check out our status at... X in the original water were in the following is correct we down... In cationic sizes do not dissolve in NaOH solution but not anhydrous beryllium is... White solids P Bahadur IIT-JEE Previous year Narendra Awasthi MS Chauhan metal covalent! Sulphates in water increase as you go down the group mainly due the! Science Foundation support under grant numbers 1246120, 1525057, and barium are basic and do make. Be ( OH ) _2 \$ in 0.1 m NaOH nuclear charge as the radius goes increasing... In electronegativities increases down the group metals are thermally stable H in water is called: View solution be soluble! Are insoluble in their respective periods content is licensed by CC BY-NC-SA 3.0 khinch kar the water! Exhibits anomalous properties not exist solution of K O H in water is 1:23 200+ LIKES other hand of. ) on metals, metal oxides, hydroxides or carbonate noted, LibreTexts content is licensed by CC 3.0!