How much volume of methanol is needed to prepare 2.5 L of a 0.25 M solution, if the density of methanol is 0.793 kg/L?

1. 22.25 mL
2. 24.78 mL
3. 25.22 mL 
4. 28.52 mL

If the mass of air per unit area 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). Calculate the molality of chloroform in this water sample, which represents the number of moles of chloroform dissolved per kilogram of pure water solvent:

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

In a reaction A + B₂ → AB_2, 
A will act as a limiting reagent if :

 
Choose the correct option:

If 10 volumes of H₂ react completely with 5 volumes of O₂, what volume of water vapor will be produced under the same conditions of temperature and pressure?

1. 9

2. 8

3. 10

4. 11

15.15 pm in the basic unit will be 

1. 1.515 × 10^–12 m

2. 2.57 × 10^–11 m

3. 2.87 × 10^–11 m

4. 1.515 × 10^–11 m

Which will have the largest number of atoms among the following?