The number of molecules of H2SO4 present in 100 mL of 0.02 M H2SO4 solution are: 

1. 12.044×1020 molecules

2. 6.022×1023 molecules

3. 1×1023 molecules

4. 12.044×1023 molecules

Hint:  Use the formula, Number of moles = molarity×volumeinL

Explanation:

Step 1:

One mole of any substance contains 6.022×1023 atoms/molecules

Hence, Number of millimoles of H2SO4
=molarity×volumeinL

=0.02×100×1L1000
=2×10-3mol
Step 2:
 Numberofmolecules=numberofmolecules×N

=2×10-3×6.022×1023

=12.044×1020molecules