What weight of sodium hydroxide is required to neutralise $100 \ mL$ of $0.1 \ N - HCl$ (in $g$)?

At $300 \ K$ and $1 \ atm$,$15 \ mL$ of a gaseous hydrocarbon requires $375 \ mL$ of air containing $20 \% \ O_2$ by volume for complete combustion. After combustion,the gases occupy $330 \ mL$. Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure,the formula of the hydrocarbon is:

The concentration of a $100 \ mL$ solution containing $X \ g$ of $Na_2CO_3$ (molecular weight $= 106$) is $Y \ M$. The values of $X$ and $Y$ are respectively.

How many moles of $NaOH$ are present in $27 \, mL$ of $0.15 \, M \, NaOH$?

Phosphine $[PH_{3(g)}]$ decomposes to produce vapours of phosphorus $(P_4)$ and $H_2$ gas. What will be the change in volume when $100 \ mL$ of phosphine is decomposed?

The right option for the mass of $CO_2$ produced by heating $20 \ g$ of $20 \%$ pure limestone is $........ \ g$ (Atomic mass of $Ca = 40$) $[CaCO_3 \stackrel{1200 \ K}{\longrightarrow} CaO + CO_2]$