Question

42. The number of molecules in 100 ml of 0.02 N
H2SO4 is
(a) 6.02 x 1022
(b) 6.02 x 1021
(c) 6.02 x 1020
(d) 6.02 x 1018​

Answer 1

H2SO4 → SO42- + 2H+

Since one mole of H2SO4 = 2 moles equivalents of H+

Therefore, molarity = normality/2

                                    = 0.01 M  

Now, 0.01M = 0.01=no. of moles of H2SO4×1000Volume of solution in mlOrNo of moles=0.01×100 1000=0.001 mol

We know that 

No of molecules in one mole = 6.022×1023

Therefore, no of molecules in 0.001 mol = 0.001×6.022×1023, i.e 0.006 ×1023molecules.

Answer 2

42. The number of molecules in 100 ml of 0.02 N

H2SO4 is

(a) 6.02 x 1022

(b) 6.02 x 1021✔

(c) 6.02 x 1020

(d) 6.02 x 1018