Which metal bicarbonates does not exist in solid state?<br>(i) LiHCO3 (ii) Ca(HCO3)2 (iii) Zn(HCO3)2 — s Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Reducing power in aqueous solution is measured by the standard reduction potential (E°). The total energy change depends on three steps: sublimation (M_s -> M_g), ionization (M_g -> M+_g), and hydration (M+_g -> M+_aq). Step 2: Lithium has the highest ionization energy among alkali metals, which works against it being a strong reducing agent. However, due to its exceptionally small cationic size, Li+ has an extremely high enthalpy of hydration. Step 3: This massive release of hydration energy more than compensates for its high sublimation and ionization energies, making lithium the strongest reducing agent in water. Thus, hydration energy is the key factor (option b).