In the balanced combustion reaction of $1 \, mol$ of $C_xH_{2n-2}$ hydrocarbon,the coefficients of $O_2$,$CO_2$,and $H_2O$ will be respectively ...

At $STP$,the volume of $4.4 \, g$ of an unknown gas is $2.24 \, L$. Which of the following is this gas?

Thermite is a mixture of $X$ parts of ferric oxide and $Y$ parts of aluminium powder. What are $X$ and $Y$ respectively?

When a mixture of $4.44 \, g$ of $CaCl_2$ and $NaCl$ is treated with a sodium carbonate solution,$Ca^{2+}$ ions precipitate as $CaCO_3$. Upon heating,this precipitate yields $0.56 \, g$ of $CaO$. Calculate the percentage of $NaCl$ in the original mixture. (Atomic mass of $Ca = 40 \, g/mol$)

The hardness of a water sample (in terms of equivalents of $CaCO_3$) containing $10^{-3} \ M \ CaSO_4$ is ................... $ppm$ (Molecular mass of $CaSO_4 = 136 \ g \ mol^{-1}$)

$56.0 \ L$ of nitrogen gas is mixed with excess of hydrogen gas and it is found that $20 \ L$ of ammonia gas is produced. The volume of unused nitrogen gas is found to be $L$.