What volume of decimolar solution should be mixed in a solution of the same solute $(0.5 \, M, \, 200 \, mL)$ to make it $0.25 \, M$?

Six volumes of oxygen,on complete ozonisation,form ...... volumes of ozone.

How many grams of bromine are required to react with $21 \ g$ of $C_3H_6$? (Atomic mass of $Br = 80$)

For a reaction,$N_2O_{5(g)} \rightarrow 2NO_{2(g)} + \frac{1}{2}O_{2(g)}$ in a constant volume container,no products were present initially. The final pressure of the system when $50\%$ of the reaction is completed is:

The mass percentage composition of dry air at sea level is approximately $N_2: 63 \%$, $O_2: 16 \%$, $Kr: 21 \%$. If the total pressure is $p \ atm$, calculate the partial pressure of each component respectively. (Molecular weights: $N_2 = 28, O_2 = 32, Kr = 84$)

The volume (in $mL$) of $0.1\, N$ $NaOH$ required to neutralize $10\, mL$ of $0.1\, N$ phosphinic acid is........