What is the difference between h+ concentration in an acidic solution such as lemon juice (ph 2) and a basic solution such as household bleach (ph 13)?

The pH of solution is calculated using the formula:

pH = - log [H]

where [H] is the concentration of H+ ion in molarity

H+ concentration when pH = 2:

2 = - log [H]

[H] = 0.01 M

H+ concentration when pH = 13:

13 = - log [H]

[H] = 1 x 10^-13 M

The difference is therefore:

0.01 M - 1 x 10^-13 M = 0.01 M

The concentration at pH=13 is so small that it can be considered negligible.