Explanation
In C4 plants, sodium is a micronutrient that aids in metabolism, specifically in regeneration of phosphoenolpyruvate (involved in the biosynthesis of various aromatic compounds, and in carbon fixation) and synthesis of chlorophyll.
(1) It is comparatively harder than other alkali metals. $$Li$$ cannot be stored in kerosene as it floats to the surface, due to its very low density. $$Li$$ is generally kept wrapped in paraffin wax.
(2) It can be melted in the dry air without losing its brilliance.
(3) Unlike other alkali metals, lithium is least reactive among all. It can be noticed by the following properties,
(i) It is not affected by air.
(ii) It decomposes water very slowly to liberate $$H_2$$.
(iii) It hardly reacts with bromine while other alkali metals react violently.
(4) Lithium is the only alkali metal which directly reacts with $$N_2$$ to form lithium nitride ($$Li_3N$$)
(5) Lithium when heated in $$NH_3$$ forms amide, $$Li_2NH$$ while other metals form amides, $$MNH_2$$.
(6) When burnt in air, lithium form $$Li_2O$$ sodium form $$Na_2O$$ and $$Na_2O_2$$ other alkali metals form monoxide, peroxide and superoxide.
(7) $$Li_2O$$ is less basic and less soluble in water than other alkali metals.
(8) $$LiOH$$ is a weaker base than $$NaOH$$ or $$KOH$$ and decomposes on heating.
(9) The ion of $$Li$$ and its compounds are more heavily hydrated than those of the rest of the group
Hence, option $$B$$ is correct.
Hint: Solubility means the tendency of a species to dissolve in any solvent.
Explanation:
$$NaHCO_3$$ and $$KHCO_3$$ dissociates as-
$$NaHCO_3\rightarrow Na^++HCO_3^-$$
$$KHCO_3\rightarrow K^++HCO_3^-$$
Both of them give same annion but the size of sodium ion is less than that of potassium. So, $$NaHCO_3$$ have low lattice energy than $$KHCO_3$$ and its tendency to dissolve in water is also low.
$$CaCO_3$$ dissociates as-
$$CaCO_3\rightarrow Ca^{+2}+CO_3^{2-}$$.
$$Ca^{+2}$$ have high charge density than $$K^+,Na^+$$ so, it have low lattice energy than sodium bicarbonate and potassium bicarbonate and also have the lowest solubility.
The increasing order of solubility is-
$$CaCO_3<NaHCO_3<KHCO_3$$.
Fianl Answer: The increasing order of solubility is-
$$CaCO_3,NaHCO_3,KHCO_3$$.
Correct option (D).
Option $$(E)$$ is correct.
Potassium hydroxide is a good conductor of an electric current in the molten (fused) state and in aqueous solution. When it is in solid state it cannot conduct electricity but it can conduct electricity in aqueous solution state or molten state. This is because it is an ionic compound. Ionic compounds are made of charged ions which are held tightly in solid state but become mobile in molten or aqueous solution state. The movement of these mobile ions between electrodes helps in conducting electricity.
Hence, option $$A$$ is the correct answer.
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