A. $\rightarrow(3)$

B. $\rightarrow(2)$

C. $\rightarrow(4)$

D. $\rightarrow(5)$

A. Li-Most negative $E^{-}$among alkali metals

[Due to very high hydration energy the resulting $E^{\ominus}$ is most negative].

B. Na-Strongest monoacidic base

[Alkalies are more acidic than alkaline earth metals. LiOH has covalent character].

C. Ca-insoluble oxalate

[Calciuim oxalate is insoluble in water]

D. Ba-Insoluble sulphate

[Hydration energy decreases as size of cation increases].

$6 s^2$ outer electronic configuration

$$\left.{ }_{56} \mathrm{Ba}=1 s^2, 2 s^2, 2 p^6, 3 s^2, 3 p^6, 3 d^{10}, 4 s^2, 4 p^6, 4 d^{10}, 5 s^2, 5 p^6, 6 s^2\right]$$

A. $\rightarrow$ (3)

B. $\rightarrow$ (4)

C. $\rightarrow(2)$

D. $\rightarrow 1$

A. $\mathrm{CaCO}_3-$ Manufacture of high quality paper

B. $\mathrm{Ca}(\mathrm{OH})_2-$ Used in white washing

C. $\mathrm{CaO}-$ Manufacture of sodium carbonate from caustic soda

D. $\mathrm{CaSO}_4-$ Dentistry, ornamental work

A. $\rightarrow$ (6)

B. $\rightarrow$ (4)

C. $\rightarrow(2)$

D. $\rightarrow$ (3)

E. $\rightarrow$ (5)

F. $\rightarrow 1$

Elements with the characteristic flame colour are as follows

A. Cs - Blue

B. $\mathrm{Na}-$ Yellow

C. K - Violet

D. Ca - Brick red

E. Sr - Crimson red

F. Ba - Apple green

Flame colours are produced from the movement of the electrons in the metal ions present in the compounds. These movement of electrons (electronic excitation-de-excitation) requires energy.

Each atom has particular energy gap between ground and excited energy level therefore each of these movements involves a specific amount of energy emitted as light energy, and each corresponds to a particular colour. As we know energy gap between ground and excited state energy level increases wavelength of decreases and complemently colouer is observed as a result.