Long Answer TypeExplain why can alkali and alkaline earth metals not be obtained by chemical reduction methods?
Short Answer TypeLong Answer TypeCompare 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.
Starting with sodium chloride how would you proceed to prepare (i) sodium metal (ii) sodium hydroxide (iii) sodium peroxide (iv) sodium carbonate?
Describe the importance of the following: (i) limestone (ii) cement (iii) plaster of paris.
Importance of limestone
It is used in the manufacture of quick lime.
CaCO3 --> CaO +CO2
Quicklime, when added to water in limited amount, is used to produce slaked lime or milk of lime Ca(OH)2
CaO +H2O ---> Ca(OH)2
It is used as a flux to remove acidic impurities
CaO +SiO2 ---> CaSiO3
6CaO + P4O10--> 2Ca3(PO4)2
The importance of cement: Cement is an important building material. it is used in the concrete and reinforced concrete, in plastering and in the construction of dams, bridges and buildings.
The importance of plaster of Paris:On heating gypsum at 373 K, it loses water molecules and becomes calcium sulphate hemihydrate plaster of Paris.Plaster of Paris is a white powder and on mixing with water, it changes to gypsum once again giving a hard solid mass. It is used for immobilising the affected part where there is a bone fracture. It is used for making statues, models and other decorative materials.
Multiple Choice QuestionsAmongst the following, select the element having highest ionization enthalpy.
Sodium
Potassium
Beryllium
Magnesium
The main oxides formed on combustion of Li, Na and K in excess of air are, respectively:
LiO2, Na2O2 and K2O
LiO2, Na2O2 and KO2
LiO, Na2O2 and KO2
LiO, Na2O2 and KO2
Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?
CaSO4
BeSO4
BaSO4
BaSO4
The correct statement for the molecule, CsI3 is
It is a covalent molecules
It contains Cs+ and I3-
It contains Cs3+ and I- ions
It contains Cs3+ and I- ions
Which of the following on thermal decomposition yields a basic as well as an acidic oxide?
NaNO3
KClO3
CaCO3
CaCO3
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