(i) → (c)

As Li has the most negative E^⊖ value due to the high hydration energy.

(ii) → (b)

As Alkali metals are more acidic than the given alkaline earth metals, while Li base is covalent in nature.

(iii) → (d)

Calcium oxalate is insoluble in water

(iv) → (a)

Due to the high hydration energy.

(iv) → (e)

Electronic configuration of Ba is 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p⁶6s².