In an iron oxide, the mass percent of iron and oxygen are 69.9 and 30.1, respectively. The empirical formula of the oxide of iron will be:

1. Fe₃O₂

2. Fe₂O₂

3. Fe₂O₃

4. Fe₃O₄

The average atomic mass of chlorine using the following data would be:

1. 38.4527 u

2. 37.4527 u

3. 36.4527 u

4. 35.4527 u

The number of moles of hydrogen atoms present in 3 moles of ethane (C₂H₆), will be-

1. 18.069 × 10²³

2. 1.8 × 10²³

3. 18

4. 6 × 10²³

20 g of sugar is dissolved in enough water to make a final volume of 2L. The concentration of sugar (C₁₂H₂₂O₁₁) in mol L^–1  will be:

1. 0.29 mol/L

2. 0.029 mol/L

3. 0.35 mol/L

4. 0.032 mol/L

If the density of methanol is 0.793 kg L^–1, the volume needed for making 2.5 L of its 0.25 M solution would be: 

1. 22.25 mL

2. 24.78 mL

3. 25.22 mL 

4. 22.52 mL

If the mass of air at sea level is 1034 g cm^–2, pressure in pascal will be:

1. 1.01332 × 10⁵ Pa

2. 1.01332 × 10⁶ Pa

3. 1.01332 × 10⁷ Pa

4. 1.01332 × 10⁸ Pa

The SI unit of mass is:

1. Kilogram (kg)

2. Gram (g)

3. Pascal (Pa)

4. Kilometres (km)

A significant figure is defined as :

The chloroform contamination level in water is 15 ppm (by mass of chloroform). The molality of chloroform in the water sample would be:

1. 3.25 × 10^-4   

2. 1.5 × 10^-3 

3.  7.5 × 10^-3    

4. 1.25 × 10^-4  

If the speed of light is 3.0 × 10⁸ m s^–1, then the distance covered by light in 2.00 nanoseconds will be -

1. 0.500 m

2. 0.600 m

3. 0.700 m

4. 0.800 m