Why are ionic hydrides of only alkali metals and alkaline earth metals are known? Give two examples.
Alkali metals and alkaline earth metals are most electropositive due to low ionization ethalpy therefore they form ionic hydrides, e.g. NaH, KH and CaH2
The alkali metals are low melting. Which of the following alkali metals is expected to melt if the room temperature rises to 30 °C?
(a) Na (b) K (c) Rb (d) Cs
Lithium resembles magnesium in some of its properties. Mention two such properties and give reasons for this resemblance.
Why are alkali metals always univalent? Which alkali metal ion forms largest hydrated ion in aqueous solution?
Discuss the trend of the following:
(i) Thermal stability of carbonates of Group 2 elements.
(ii) The solubility and the nature of oxides, of Group 2 elements.
Which of the following compounds are readily soluble in water?
(a) BeS04
(b) MgS04
(c) BaS04
(d) SrS04
Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous?
Arrange the following in the increasing order of solubility in water.
MgCl2, CaCl2, SrCl2, BaCl2
Why does the solution of alkali metals becomes blue in liquid ammonia? Give the chemical equation also.
Why is LiF almost insoluble in water whereas LiCl soluble not only in water but also in acetone?
Match the compounds given in Column I with their uses mentioned in Column II.
| Column I | Column II |
| (i) CaC03 | (a) Dentistry, ornamental work |
| (ii) Ca(OH)2 | (b) Manufacture of sodium carbonate from caustic soda |
| (iii) CaO | (c) Manufacture-of high quality paper |
| (iv) CaS04 | (d) Used in white washing |
Match the elements given in Column I with the colour they impart to the flame given in Column II.
| Column I | Column II |
| (i) Cs | (a) Apple green |
| (ii) Na | (b) Violet |
| (iii) K | (c) Brick red |
| (iv) Ca | (d) Yellow |
| (v) Sr | (e) Crimson red |
| (vi) Ba | (f) Blue |
Which one of the following alkaline earth metal carbonates is thermally most stable?
(a) MgCO3 (b) CaCO3 (c) SrCO3 (d) BaCO3
In the synthesis of sodium carbonate, the recovery of ammonia is done by treating NH4C1 with Ca(OH)2. The by-product obtained in this process is
(a) CaCl2
(b) NaCl
(c) NaOH
(d) NaHC03
Choose the correct statements from the folio-wing.
(a) Beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal.
(b) Beryllium sulphate is readily soluble in water as the greater hydration enthalpy of Be2+ overcomes the lattice enthalpy factor.
(c) Beryllium exhibits coordination number more than four.
(d) Beryllium oxide is purely acidic in nature.
(a) What makes lithium to show properties uncommon to the rest of the alkali metals?
(b) When is a cation highly polarising? Which alkali metal cation has the highest polarising power?
The reducing power of a metal depends oh various factors. Suggest the factor which makes Li, the strongest reducing agent in aqueous solution.
(a) Sublimation enthalpy (b) Ionisation enthalpy
(c) Hydration enthalpy (d) Electron-gain enthalpy
All compounds of alkali metals are easily soluble in water but lithium compounds are more soluble in organic solvents. Explain.
Match the elements given in Column I with the properties mentioned in Column II.
| Column I | Column II |
| (i) Li | (a) Insoluble sulphate |
| (ii) Na | (b) Strongest monoacidic base |
| (iii) Ca | (c) Most negative E ° value among alkali metals |
| (iv) Ba | (d) Insoluble oxalate ‘ |
| (e) 6s2 outer electronic configuration |
Write the chemical formula of the following compounds.
(i) Chile salt petre (ii) Marble (iii) Brine
Which of the following statements is true about Ca(OH)2?
(a) It is used in the preparation of bleaching powder.
(b) It is a light blue solid.
(c) It does not possess disinfectant property.
(d) It is used in the manufacture of cement.
Which of the following are the correct reasons for anomalous behaviour of lithium?
(a) Exceptionally small size of its atom.
(b) Its high polarizing power.
(c) It has high degree of hydration.
(d) Exceptionally low ionization enthalpy.
Which one of the following alkali metals give hydrated salts?
(a) Li (b) Na (c) K (d) Cs
What is the effect of heat on the following compounds (Give equations for the reactions)? (i) CaC03 (ii) CaSO4 2H2O
Metallic elements are described by their standard electrode potential, frision enthalpy, atomic size, etc. The alkali metals are characterized by which of the following properties?
(a) High boiling point. ‘
(b) High negative standard electrode potential.
(c) High density.
(d) Large atomic size.
When heated in air, the alkali metals form various oxides. Mention the oxides formed by Li, Na and K.
Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals.
(a) Nitrates (b) Carbonates (c) Sulphates
Describe two important uses of each of the following: ,
(i) caustic soda (ii) sodium carbonate (iii) quick lime
Write balanced equations for reactions between.
(a) Na2O2 and water
(b) KO2 and water
(c) Na2O and CO2
Explain the following:
(a) Lithium iodide is more covalent than lithium fluoride.
(b) Lattice enthalpy of LiF is maximum among all the alkali metal halides.
Which of the carbonates given below is unstable in air and is kept in C02 atmosphere to avoid decomposition.
(a) BeCO3
(b) MgC03
(c) CaC03
(d) BaCO3
Some of the Group 2 metal halides are covalent and soluble in organic solvents. Among the following metal halides, the one which is soluble in ethanol is
(a) BeCl2
(b) MgCl2
(c) CaCl2
(d) SrCl2