List of practice Questions

The density of 2 M aqueous solution of NaOH is 1.28 g/cm$^3$. The molality of the solution is [Given that molecular mass of NaOH = 40 g mol$^{-1}$]
In which case is the number of molecules of water maximum ?
The bond dissociation energies of X2 , Y2 and XY are in the ratio of 1 : 0·5 : 1. ΔH for the formation of XY is – 200 kJ mol–1 . The bond dissociation energy of X2 will be
Suppose the elements $X $ and $Y$ combine to form two compounds $XY_2$ and $X_3Y_2$. When $0.1$ mole of $XY_2$ weighs $10\, g$ and $0.05$ mole of $X_3Y_2$ weighs $9\, g$, the atomic weights of $X$ and $Y$ are
The percentage of pyridine (C5H5N) that forms pyridinium ion (C5​H5​N+H) in a 0.10 M aqueous pyridine solution (Kb​ for C5H5N = 1.7×10−9) is
1.0 g of magnesium is burnt with 0.56 g O2 in a closed vessel. Which reactant is left in excess and how much ?
(At. wt. Mg =24; O=16)
When 22.4 litres of H2(g) is mixed with 11.2 litres of Cl2 (g), each at S.T.P., the moles of HCl (g) formed is equal to :
Equal masses of H2, O2 and methane have been taken in a container of volume V at temperature 27°C in identical conditions. The ratio of the volumes of gases H2 : O2 : methane would be :
The number of moles of $KMnO_4$ that will be needed to react with one mole of sulphite ion in acidic solution is
Specific volume of cylindrical virus particle is $6.02 \times 10^{-2}$ cc/g, whose radius and length are $7 \mathring{A} \, and \, 10\mathring{A}$ respectively. If $N_A = 6.023 \times 10^{23},$ find molecular weight of virus.
The number of moles of oxygen in 1 L of air containing 21% oxygen by volume, under standard conditions, is
The percentage weight of Zn in white vitriol $[ZnSO_4 . 7H_2O]$ is approximately equal to $(at. \, mass\, of \, Zn= 65, S=32, 0=16 \, and \, H= 1)$
The number of gram molecules of oxygen in $6.02 \times 10^{24}$ CO molecules is