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Question 10.1, , What are the common physical and, chemical features of alkali metals?, , Answer., Physical properties of alkali metals:, o They have low ionization enthalpies., , o They are highly electropositive in, nature., , o They exhibit +1 oxidation states in, their compounds., , o They impart characteristic color to the, flame., , Chemical properties of alkali metals:, , o Their hydroxides are highly basic in, nature., , o They are highly reactive in nature., , o They dissolve in liquid ammonia to, form blue and conducting solution.

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Question 10.2, , Discuss the general characteristics and, gradation in properties of alkaline earth, metals., , Answer., Properties of Alkaline Earth Metals:, , o Atomic size goes on increasing down, the group., , o They are harder than alkali metals., , o lonization energy goes on decreasing, down the group., , o Electropositive character increases on, going down the group., , o They are less electropositive than, alkali metals.

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Why are the alkali metals not found in, nature?, , Answer., , Alkali metals are highly reactive nature., This is why, they always exist in combined, State in nature., , Question 10.4, , Find out the oxidation state of sodium in, Na,0.., , Answer., , Let x is the oxidation state of Na in Na.0.,., 2x + 2 (-1)=0, , 2x-2=0, , DX =P., , eo | Up

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Question 10.5, , Explain why is sodium less reactive than, potassium., , Answer., , Sodium is less reactive than potassium, because ionization enthalpy of K is 419 kJ, mol,, , lonization enthalpy of sodium = 496 kJ, mol., , Hence, ionization enthalpy of potassium is, less than that of sodium, potassium is, more reactive than sodium.

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Question 10.6, , Compare the alkali metals and alkaline, earth metals with respect to, , (i) ionization enthalpy (ii) basicity of, oxides (iii) solubility of hydroxides., , Answer., , o Jonization enthalpy of alkaline metals, is higher because of high nuclear, charge and smaller atomic size ., , o Basicity of oxides of alkali metals is, higher than that of alkaline earth, metals., , o Solubility of hydroxides of alkali metals, is higher due to lower ionization, enthalpy., , o Due to lower ionization enthalpy, alkali, metals are more electropositive.