Question

100 ml of a solution containing 18.25 grams HCl was heated when 10^23 numbers of HCl molecules were lost. the bumbers of HCl molecules left in the solution will be???​

Answer 1

Given info : 100 ml of a solution containing 18.25 grams HCl was heated when 10^23 numbers of HCl molecules were lost.

To find : the number of HCl molecules left in the solution will be ...

solution : initially, mass of HCl = 18.25g

10²³ molecules were lost after heating,

so the mass of 10²³ molecules of HCl = no of moles of HCl × molecular weight of HCl

                                                               = 10²³/6.023 × 10²³ × 36.5 = 6.06 g

therefore the mass of HCl left in the solution = 18.25 - 6.06 = 12.19 g

now the no of HCl molecules left in the solution = 12.19/36.5 × 6.023 × 10²³ ≈  2 × 10²³ molecules