The properties of lithium and beryllium and their compounds differ far from those of the group $1$ and group $2$ elements and compound may show closer similarities with group- $2$ elements (particularly $\mathrm{Mg}$ ) then they show towards their own group. Similarly, $\mathrm{Be}$ is also closer to $\mathrm{Al}$.

Diagonal relationships do not exist between the pair of:

The properties of lithium and beryllium and their compounds differ far from those of the group $1$ and group $2$ elements and compound may show closer similarities with group- $2$ elements (particularly $\mathrm{Mg}$ ) then they show towards their own group. Similarly, $\mathrm{Be}$ is also closer to $\mathrm{Al}$.

Which of the following metals react directly with carbon?

$\begin{array}{llll}\text{ (I) }\mathrm{Li}& \text{ (II) }\mathrm{Na}& \text{ (III) }\mathrm{Mg}& \text{ (IV) }\mathrm{Ca}\end{array}$

A white solid is either ${\mathrm{Na}}_2\mathrm{O}$ or ${\mathrm{Na}}_2{\mathrm{O}}_2.$ A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid.

Identify the substance and explain with balanced equation.

A white solid is either ${\mathrm{Na}}_2\mathrm{O}$ or ${\mathrm{Na}}_2{\mathrm{O}}_2.$ A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid.

Explain what would happen to the red litmus if the white solid were the other compound.

A compound $\left(\mathrm{X}\right)$ imparts a golden yellow flame and shows the following reactions:

Zinc powder, when boiled with a concentrated aqueous solution of $\left(\mathrm{X}\right)$ dissolves and hydrogen, is evolved.

A compound $\left(\mathrm{X}\right)$ imparts a golden yellow flame and shows the following reactions:

 When an aqueous solution of $\left(\mathrm{X}\right)$ is added to an aqueous solution of stannous chloride, a white precipitate is obtained first which dissolves in excess of solution of $\left(\mathrm{X}\right)$. Identify $\left(\mathrm{X}\right)$ and write equations at steps $\left(\mathrm{i}\right)$ and $\left(\mathrm{ii}\right)$.

Explain the following:

$\mathrm{NaCl}$ is not hygroscopic but table salt on exposure to air damps up.

Explain the following:

Unlike ${\mathrm{Na}}_2{\mathrm{CO}}_3, {\mathrm{K}}_2{\mathrm{CO}}_3$ cannot be prepared by Solvay ammonia soda process.

Explain the following:

Standard solution of $\mathrm{NaOH}$ cannot be prepared by direct weighing.