Answer is: tomatoes is thousand (1000) times more acidic than water.
pH(tomato) = 4.00.
pH(water) = 7.00.
pH = -log[H⁺].
[H⁺] = 10∧(-pH); concentration of hydrogen ions.
[H⁺] = 10⁻⁴ M = 0.0001 M; tomato.
[H⁺] = 10⁻⁷ M = 0.0000001 M; water.
[H⁺](tomato) /[H⁺](water) = 0.0001 M ÷ 0.0000001 M.
[H⁺](tomato) /[H⁺](water) = 1000.
