A mixture consists of hydrogen and oxygen gases in the mass ratio 1 : 4. Determine the mole ratio of hydrogen molecules to oxygen molecules present in the mixture.

1.	1:4	2.	4:1
3.	16:1	4.	2:1

Which of the following represents the volume occupied by a single water molecule, assuming the density of water is \(1\,\text{g cm}^{-3}\)?

1.  $9.0\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

2. $\mathrm{ 6}.023\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

3. $\mathrm{ 3}.0\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

4. $\mathrm{ 5}.5\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

What volume of oxygen gas is required for the complete combustion of 1 L of propane gas, C₃H₈, when both gases are measured at 0°C and 1 atm?
1. 7 L
2. 6 L
3. 5 L
4. 10 L

What is the number of moles of PbCl₂ formed when 6.5 g of PbO reacts with 3.2 g of HCl?

1. 0.044
2. 0.333
3. 0.011
4. 0.029

Which of the following volumes of concentrated H₂SO₄ (98% by mass, density = 1.80 g/mL) is required to prepare 1 L of 0.1 M H₂SO₄ solution?

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

Cisplatin, an anticancer drug, has the molecular formula $\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_2<mspace\; width="1em"></mspace>{\mathrm{Cl}}_2$. What is the mass (in gram) of one molecule? (Atomic weights : Pt=195, H=1.0, N=14, Cl=35.5)

1.  $4.98\times {10}^{-21}$

2.  $4.98\times {10}^{-22}$

3.  $6.55\times {10}^{-21}$

4.  $3.85\times {10}^{-22}$

The conversion of oxygen to ozone occurs to the extent of 15% only. The mass of ozone that can be prepared from 67.2 L oxygen at 1 atm and 273 K will be:

1. 14.4 gm

2. 96 gm

3. 640 gm

4. 64 gm