What is the final pH after 1 drop (0.05 mL) of 6 M HCI is added to 1.0 L of freshly prepared pure water that was originally at a pH of 7.0. Is there a significant pH change?

What is the final pH after 1 drop (0.05 mL) of 6 M HCI is added to 1.0 L of freshly prepared pure water that was originally at a pH of 7.0. Is there a significant pH change?

Answer:- 

                added volume = 0.05 /1000  

                                        = 0.00005 liter

    number of add moles  = molarity * volume 

                                        = 6moles / liter  * 0.00005 liter 

                                        =0.0003 moles 

total volume of solution   = 1.0 liter  +  0.00005 liter 

                                         = 1.00005 liter 

molarity of new solution = number of moles / volume in liter 

                                        =0.0003/1.00005 

                                        = 2.99x10^-4

    pH is this new solution= - log [H+]

Reaction is HCl  ----------> H+   +   Cl -

                            so [H+] = 2.99x10^-4

                         hence PH =  - log 2.99x10^-4

                                          =  3.52 

Hence there are big change in pH value

Answer  :- yes there are significant change in pH value