Sulphuric acid used in Lead Storage battery has a concentration of $$4.5 \mathrm{~M}$$ and a density of $$1.28 \mathrm{~g} / \mathrm{~ml}$$. The molality of the acid is __________.

When 1 mole of $$\mathrm{O}_2$$ and 1 mole of ammonia are made to react in the reaction,

$$4 \mathrm{NH}_3(\mathrm{~g})+5 \mathrm{O}_2(\mathrm{~g}) \rightarrow 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_2 \mathrm{O}(\mathrm{g})$$

A given mass of a hydrocarbon on complete combustion produced $$176 \mathrm{~g}$$ of $$\mathrm{CO}_2$$ and $$90 \mathrm{~g}$$ of $$\mathrm{H}_2 \mathrm{O}$$. What is the Molecular formula of the compound?

$$15 \mathrm{~g}$$ of $$\mathrm{CaCO}_3$$ completely reacts with