(iii) Solubility of hydroxides of alkali metals are higher than that of alkaline earth metals. Answer: Since group 1 hydroxides and carbonates due to large size contain higher hydration energy than the lattice energy so, they are easily soluble in water. (c) Lithium does not form alums. Reactivity of halogen towards particular alkali metal follows the order F 2 > Cl 2 > Br 2 > I 2 ... Alkali metal nitrates (MNO 3) decompose on strong heating to corresponding nitrite and O 2 ... as corresponding slats of other alkali metals are freely soluble vi) Li form imide ( LiNH) with ammonia while other alkali metals form amides ( MNH 2) Explain. Therefore, it is almost insoluble in water. Answer: It is called Nitrolime. plays important roles in neuromuscular function. Question 8. This is because their hydration energies decreases more rapidly than their lattice energies. Berrylium hydroxide ( Be(OH) 2) and magnesium hydroxide ( Mg(OH) 2) are completely insoluble in water. This website has definitions for soluble, insoluble and slightly soluble plus a good set of rules for solubility at the end of the file. (c)Due to the small size of Li+ it has a strong positive field which attracts the negative charge so strongly that it does not permit the oxide ion, 02- to combine with another oxygen atom to form peroxide ion. This substance does not exist; it cannot be isolated as a pure substance. (ii) 2Na + O2 ———> Na2O2 Answer: Alkali metals dissolve in liquid ammonia and give deep blue solutions which are conducting in nature because ammoniated electrons absorb energy in the visible region of light and impart blue colour. Other solubility tables can be seen via this solubility table search. Nitrate and Alkali Metal rule 2. The most important slightly soluble substance is calcium hydroxide, Ca(OH)2. At cathode: Therefore, a large amount of energy is needed to excite their valence electron, and that’s why they do not impart colour to the flame. (i) CaC03 (ii) CaSO4 2H2O Answer: (a) Na2O2 + 2H2O ——-> 2Na0H + H2O2 On moving down the group, their solubility decreases. All enzymes that utilise ATP in phosphate transfer require magnesium as a cofactor. (Acetone is polar in nature). On the other hand, in lithium chloride (LiCl) the lattice enthalpy is comparatively very small. When heated to 800°C, NaN03 gives, (a)Na + N2 + O2 (b) NaNO2 + O2 (c) Na2O + O2 + N2 (d)NaN3 + O2, Question 4. Answer: (i) Sodium metal is manufactured by electrolysis of a fused mass of NaCl 40% and CaCl2 60% in Down’s cell at 873 K, using iron as cathode and graphite as anode. Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous? Question 23. (i) Chile salt petre (ii) Marble (iii) Brine (b) Smaller the size (internuclear distance), more is the value of Lattice enthalpy since internuclear distance is expected to be least in the LiF. Which one of the following alkaline earth metal carbonates is thermally most stable? Each rule has exceptions and the important ones are noted. Alkaline earth metal carbonates and sulphates have lower solubility than alkali metal carbonates and sulphates. Amongst fluorides of alkali metals, the lowest solubility of LiF in water is due to (a) ionic nature of lithium fluoride. The solubility of metal halides depends on their nature, lattice enthalpy and hydration enthalpy of the individual ions. From Li to Cs, thermal stability of carbonates increases. Explain. In case of sodium and potassium compounds, the magnitude of lattice enthalpy is quite small as compared of sodium and potassium that are mentioned, readily dissolve in water. 1. 2Cl-(aq) – 2e- ———> Cl2(g). Heating the nitrates. Answer: Alkali and alkaline earth metals are themselves better recucing agents, and reducing agents better than alkali metals are not available. Halogen rule 3. Answer: (i) Caustic soda Which of the following is the least thermally stable? All Cl-, Br-, and I+ compounds are soluble except for Ag+, Hg2… All So4-2 compounds are soluble except for Ca+2, Ba+2, Sr+2, H… Na+ + e– —–> Na (l) At cathode: Question 3. Which alkali metal ion forms largest hydrated ion in aqueous solution? Answer: (a) Na2CO3 is a salt of a weak acid, carbonic acid (H2CO3) and a strong base NaOH. Why alkali and alkaline earth metals cannot be obtained by chemical reduction method? Question 27. Question 3. Due to this, K and Cs are used in photoelectric cells rather than lithium. Answer: The blue colour of the solution is due to ammoniated electron which absorbs energy in the visible region of light and imparts blue colour. Electropositive character increases on going down the group. ... Alkali Metal Nitrates. Alkali metals impart characteristic colours to the flame. Explain why is sodium less reactive than potassium. Carbonates of alkaline earth metals are insoluble in water. 3. Which alkaline earth metals do not impart colour to the flame? (c) Lithium on being heated in air mainly forms the monoxide and not the peroxide. Question 8. Answer: It is because ionization enthalpy ∆Hi of potassium = 419 kJ mol -1. Trump suggests he may not sign $900B stimulus bill. What do you mean by diagonal relationship in periodic table? The rules form a list so when they seem to contradict, the higher one takes precedent. (c) Ee for M2+ (aq) + 2e– —> M(s) (where M = Ca, Sr, or Ba) is nearly constant. Some Li + are insoluble, with Li 3 PO 4 being the most common example. For example, a typical Group 2 nitrate like magnesium nitrate decomposes like this: In Group 1, lithium nitrate behaves in the same way - producing lithium oxide, nitrogen dioxide and oxygen. Answer: (i) Ionization enthalpy. Question 2. Question 6. Cl + Cl——–>Cl2 Na2CO3(s) + H2O(l)———–>2NaOH (ii) Sodium hydroxide is manufactured by electrolysis of an aqueous solution of NaCl (brine) in Castner-Kellner cell. (i) Limestone (ii) Cement (iii) Plaster of Paris. In dentistry, in ornamental work for making statues. Silver acetate, mercurous acetate, and lead acetate are moderately soluble. Question 2. 2M(NO 3) … a) Alkali metal salts are soluble and nitrate salts are not. This brings up an important part of the solubility rules: their order. All nitrate (NO 3 ¯), nitrite (NO 2 ¯), chlorate (ClO 3 ¯) and perchlorate (ClO 4 ¯) salts are soluble. (a) KO2(b) CrO5(c) Na2O2 (d) BaO2 Therefore, the hydroxides and carbonates of these metals are only sparingly soluble in water. Potassium carbonate cannot be prepared by Solvay process. (b) Lithium cannot be used in making photoelectric cells. Answer: Monohydrate (Na2CO3– H2O) is formed as a result of efflorescence. (a) Nitrates (b) Carbonates (c) Sulphates Answer: (a) Nitrates of both group 1 and group 2 elements are soluble in water because hydration energy is more than the lattice energy. Why is LiF almost insoluble in water whereas LiCl soluble not only in water but also in acetone? Nitrate and Alkali Metal rule 3. (d) all of the above Why? What is the general name for elements of group 1 ? There is no such thing as NH4OH as a separate substance which can be isolated in pure form. What is Quick lime? Answer: Due to smallest size, Li+ can polarize water molecules easily than the other alkali metal ions. CaC2 + N2 ——–> CaCN2 + C, Question 1. Alkali metal salts are soluble and nitrate salts are not. Na + C2H5OH ——–> C2H5ONa + ½ H2. (b) Lithium cannot be used in making photoelectric cells because out of all the alkali metals it has highest ionization energy and thus cannot emit electrons when exposed to light. Therefore lithium chloride dissolves in water. The reducing property of alkali metals follows the order, (a) Na < K < Rb < Cs < Li (b) K < Na < Rb < Cs < Li, (c) Li < Cs < Rb < K < Na (d) Rb < Cs < K < Na < Li. Question 2. BeCO 3 is least stable and BaCO 3 is most stable. This brings up an important part of the solubility rules: their order. Alkali metals hydroxides are highly basic in nature. The oxides of calcium, strontium, and barium are basic and the hydroxides are strongly basic. The exceptions are the alkali metal hydroxides and Ba (OH) 2. (ii) Solubility : All the carbonates of alkali metals are generally soluble in water and their solubility increase rapidly on descending the group. (a) Nitrates (b) Carbonates (c) Sulphates They have a strong tendency to lose 1 electron to form unipositive ions. Question 7. Why do alkali metals give characteristic flame colouration? (a) Lithium iodide is more covalent than lithium fluoride. Alkali metals have low ionization enthalpies. Q9. Explain the significance of sodium, potassium, magnesium and calcium in biological fluids. Why is BeCl2 soluble in organic solvent? Question 1. (b) It is used in textile industries. Answer: They are always univalent because after losing one electron, they aquire nearest inert gas configuration.Li+ forms largest hydrated cations because it has the highest hydration energy. (ii) Both BaO and BaSO4 are ionic compounds but the hydration energy of BaO is higher than the lattice energy therefore it is soluble in water. (a) The mobilities of the alkali metal ions in aqueous solution are Li+ < Na+
Mg(s) Therefore, Lattice energy of Na2CO3 is higher than that of Li2CO3. What is dead burnt plaster? Question 20. Essentially, all alkali metal (Li +, Na +, K +, Rb +, Cs +) and ammonium (NH 4 +) salts are soluble. Potassium carbonate cannot be prepared by Solvay process. Answer: Since BeCl2 is a covalent compound it is soluble in organic solvent. Answer: Physical properties of alkali metals: Question 2. (c) MgCl2 is electrolysed. 4. That is why these metals are not obtained by chemical reduction methods. (a) Sr (b) Ca (c) Be (d) Mg Alkali salts are all ionic which refers to the bonding mechanism of the crystalline solid. Explain why can alkali and alkaline earth metals not be obtained by chemical reduction method. Question 5. The most common definition for solubility is this: This definition means there are only two categories: soluble and insoluble. Question 17. The solubility data at 1 bar or saturation pressure for sodium nitrate are reviewed. (b) KO2 and water (c) A brine solution is made to react with BaCO3 to produce Na2CO3 Which of the following is used in photoelectric cells? Rule: Important Exceptions 1. What happens when crystals of washing soda are exposed to air? (4) Chlorides, bromides, and iodides are soluble Name the alkali metal which shows diagonal relationship with magnesium? (a) Pb (b) Mg (c) Ca (d) Al (a) 2. Lead and Silver rule 3. LiF is soluble in non-polar solvents like kerosene. Which one of the following alkali metals give hydrated salts? When it is added to water, Ca(OH)2 is formed. Carbonates of alkali metals are soluble in water with the exception of Li2CO 3. Why are alkali metals always univalent? Question 6. Most nitrates tend to decompose on heating to give the metal oxide, brown fumes of nitrogen dioxide, and oxygen. Which alkali metal cation has the highest polarising power? Nitrates. Nitrates of alkaline and alkali metals give corresponding nitrites except for lithium nitrate, it gives lithium oxides. Solubility: (a) Alkali metals: Nitrates, carbonates and sulphates of alkali metals are soluble in water. (d)Since, among alkali metals, lithium has the most negative electrode potential (E° = -3.04 V) so, it is the strongest reducing agent in the aqueous solution. But, experimentally, order is reverse. When heated to 800°C, NaN03 gives Question 9. As a result, the binding energy of alkali metal ions in the close-packed metal lattices are weak. Both react with nitrogen to form nitrides. of alkaline earth metals are higher than those of the corresponding alkali metals. (c) more oxidizing (d) less basic than alkali metals Answer: This is due to the reason that potassium bicarbonate (KHCO3) formed as an intermediate (when CO2 gas is passed through ammoniated solution of potassium chloride) is highly soluble in water and cannot be separated by filtration. Answer: Let x be the oxidation state of Na in Na2O2 2x + 2 (-1) = 0 2x – 2 = 0 2x = 2 x = +1. Keep in mind that there will be slight variations from table to table. 2. It is mild antiseptic for skin infections. Describe the importance of the following: Answer: (a) No common ones. You can check out similar questions with solutions below. Answer: Soda ash is anhydrous sodium carbonate (Na2CO3). The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water. 3. In the vapour state, it exists as a chlorobridged dimer. (a) Na (b) K (c) Li (d) Cs Comment on each of the following observations: 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. (a) Nitrates-Alkali and alkaline earth metal nitrates are soluble in water. 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