The property which is not shown by acids is

General characters of acids

1) pH < 7  2) Sour taste   3) React with metal to form hydrogen gas 4) Increases the ${\mathrm{H}}^{+}$ concentration in water 5) Donate ${\mathrm{H}}^{+}$ ions. Turns blue litmus → red.

General characters of bases: 1) pH > 7  2) Bitter taste 3) Slippery feel 4) Increases ${}^{-}\mathrm{OH}$ ions in water 5) Release ${}^{-}\mathrm{OH}$ ions 6) Turns red litmus to blue litmus.