Density of a $2.05 \ M$ solution of $H_2SO_4$ in water is $1.08 \ g/mL$. Find its Normality and molality.

$K_2CS_3$ can be called potassium:

Nitrogen atom has an atomic number of $7$ and oxygen has an atomic number of $8$. The total number of electrons in a nitrate ion $(NO_3^-)$ will be:

$20 \ mL$ of $2 \ M$ $NaOH$ solution is added to $400 \ mL$ of $0.5 \ M$ $NaOH$ solution. The final concentration of the solution is $.......... \times 10^{-2} \ M$. $(Nearest \ integer)$.

Green compound $(A)$ on decomposition gives gases $(B)$ and $(C)$ along with a red-brown residue. $(B)$ and $(C)$ are acidic oxides of sulphur. Gas $(B)$ gives a positive test with $KMnO_4$.
$(C) + H_2SO_4 \to (D)$ $\xrightarrow{+ [O]} (E)$ $\xrightarrow{2H_2O} (F) + H_2SO_4$
$(F)$ $\xrightarrow{K_3[Fe(CN)_6] / KOH} (G)$ $\xrightarrow{Conc. H_2SO_4} (H) \text{ (Neutral oxide, poisonous)}$
Total number of $\sigma$ bonds in $(E)$ is:

What is the importance of chemistry?