What is the mass ratio of ethylene glycol ($$\mathrm{C_2H_6O_2}$$, molar mass = 62 g/mol) required for making 500 g of 0.25 molal aqueous solution and 250 mL of 0.25 molar aqueous solution?

'25 volume' hydrogen peroxide means

Consider the reaction

$$4 \mathrm{HNO}_{3}(1)+3 \mathrm{KCl}(\mathrm{s}) \rightarrow \mathrm{Cl}_{2}(\mathrm{~g})+\mathrm{NOCl}(\mathrm{g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})+3 \mathrm{KNO}_{3}(\mathrm{~s})$$

The amount of $$\mathrm{HNO}_{3}$$ required to produce $$110.0 \mathrm{~g}$$ of $$\mathrm{KNO}_{3}$$ is

(Given: Atomic masses of $$\mathrm{H}, \mathrm{O}, \mathrm{N}$$ and $$\mathrm{K}$$ are $$1,16,14$$ and 39, respectively.)

$$ \begin{aligned} &\mathrm{C}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})+400 \mathrm{~kJ} \\ &\mathrm{C}(\mathrm{s})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}(\mathrm{g})+100 \mathrm{~kJ} \end{aligned} $$

When coal of purity 60% is allowed to burn in presence of insufficient oxygen, 60% of carbon is converted into 'CO' and the remaining is converted into '$$\mathrm{CO}_{2}$$'. The heat generated when $$0.6 \mathrm{~kg}$$ of coal is burnt is _________.