At $S.T.P.$,$1 \ g$ $CaCO_3$ on decomposition gives $CO_2$ ............. $litres$.

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which of the following is the gas?

$A$ spherical ball of radius $7 \ cm$ contains $56 \ w\%$ iron. Find out the number of moles of iron present approximately in the ball (in $.1$)? $(d = 1.4 \ g \ cm^{-3}; \text{atomic mass} = 56 \ g \ mol^{-1})$

How many grams of dihydrogen are required to react with dinitrogen to produce $34 \ g$ of ammonia (in $g$)?

An aqueous solution of $4.5 \ g$ oxalic acid $(H_2C_2O_4)$ is made up to $250 \ mL$. Calculate the volume of $0.1 \ N$ $NaOH$ required to neutralize completely $20 \ mL$ of this solution.

The charge carried by $1 \text{ millimole}$ of $M^{n+}$ ions is $193 \text{ C}$. The value of $n$ is