What is the pH of a solution after 50 mls of distilled water is added?

Question

Assume one prepares a buffer having a pH of 4.76 by disolving 0.2 moles of CH3COOH plus 0.2 moles of NaCH3COO in 500 mls of distilled water/ After the buffer is prepared one then adds 500 mls more of distilled water to the solution. What is the pH after the 500 mls of distilled water is added?

Answer 1

it is the same.... 4.76

Henderson–Hasselbalch equation

pH = pKa + log [acetate] / [acid]

both concentrations were 0.2 moles / 500 ml

now both concentrations are 0.2 moles / 1000ml

when concentrations match, [acetate] / [acid] = 1

& the  log [acetate] / [acid] = zero

pH still equals pKa ,  4.76

Answer 2

NOOOOOOOOOO!

THINK,IF U SPILL U BUFFER SOLUTION INTO THE OCEAN,

THE HOLE OF IT WILL HAVE pH 4.76?

IN THE  ABOVE EQN WATERSHOULD BE CONSIDERED,

WITH pKa=Ka=14.WATER IS AMPHOLITE

MOREOVER ,PROBLEM IS INCORECT,CH3COOH

HAS A pKa=4.76