What is the empirical formula of vanadium oxide, if 2.74 g f the metal oxide contains 1.53 g of metal:

1.  ${\mathrm{V}}_2{\mathrm{O}}_3$

2.  VO

3.  ${\mathrm{V}}_2{\mathrm{O}}_5$

4.  ${\mathrm{V}}_2{\mathrm{O}}_7$

A metal M forms the sulphate ${\mathrm{M}}_2{\left({\mathrm{SO}}_4\right)}_3$. A 0.596 gram sample of the sulphate reacts with excess ${\mathrm{BaCl}}_2$ to give 1.220 g ${\mathrm{BaSO}}_4$. What is the atomic weight of M?     (Atomic weights : S=32, Ba=137.3)

1.  26.9

2.  69.7

3.  55.8

4.  23

One mole of elements X has 0.44 times the mass of one mole of element Y. One atom of elements X has 2.96 times the mass of one atom of $\raisebox{1ex}{$12$}\!\left/ \!\raisebox{-1ex}{$\mathrm{C}$}\right.$. What is the atomic weight of Y?

1.  80

2.  15.77

3.  46.67

4.  40.0

Hydrogen and oxygen combine to form  ${\mathrm{H}}_2{\mathrm{O}}_2$ and ${\mathrm{H}}_2\mathrm{O}$ containing 5.93% and 11.2% hydrogen, respectively. This data illustrates:

1.  Law  of conversation of mass
2.  Law of constant proportion
3.  Law  of reciprocal proportion
4.  Law of multiple proportions

The vapour density of a mixture containing ${\mathrm{NO}}_2$ and ${\mathrm{N}}_2{\mathrm{O}}_4$ is 27.6. The mole fraction of ${\mathrm{N}}_2{\mathrm{O}}_4$ in the mixture is:

1.  0.1

2.  0.2

3.  0.5

4.  0.8

Density of dry air containing only ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$ is 1.15 g/L at 740 mm and 300 K. What is % composition of ${\mathrm{N}}_2$ by weight in the air?

1. 78%

2. 75.5%

3. 80.5%

4. 72.75%

Common salt obtained from sea-water contains 8.775% NaCl by mass. The number of formula units of NaCl present in 25 g of this salt is:

1.  $3.367\times {10}^{23} \mathrm{formula} \mathrm{units}$

2.  $2.258\times {10}^{22} \mathrm{formula} \mathrm{units}$

3.  $3.176\times {10}^{23} \mathrm{formula} \mathrm{units}$

4.  $4.73\times {10}^{25} \mathrm{formula} \mathrm{units}$

Total number of moles of oxygen atoms in 3 litre ${\mathrm{O}}_3$(g) at 27$°$C and 8.21 atm are:

1.  3

2.  4

3.  1

4.  none of these

What is the number of moles of O-atom in 126 amu of ${\mathrm{HNO}}_3$:

1.  $2$

2.  $\frac{2}{{\mathrm{N}}_{\mathrm{A}}}$

3.  $6$

4.  $\frac{6}{{\mathrm{N}}_{\mathrm{A}}}$

What volume of ${\mathrm{O}}_2\left(\mathrm{g}\right)$ measured at 1 atm and 273 K will be formed by the action of 100 mL of 0.5 N KMnO₄ on hydrogen peroxide in an acid solution?

The skeleton equation for the reaction is

${\mathrm{KMnO}}_4+{\mathrm{H}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2{\mathrm{O}}_2$$\to {\mathrm{K}}_2{\mathrm{SO}}_4+{\mathrm{MnSO}}_4+{\mathrm{O}}_2+{\mathrm{H}}_2\mathrm{O}$

1.  0.12 litre

2.  0.028 litre

3.  0.56 litre

4.  1.12 litre