Which one of the following is not a property of a base?
a.) it turns litmus blue
b.)it's ph is greater than 7
c.)it has a bitter taste
d.)it has a high concentration of [h+]

D. A high concentration of H+ is acidic.

Let's recall the characteristics of bases.

1. they have pH greater than 7 because remember that in this scale, less than 7 is acidic

2. they taste bitter while acids taste sour

3. they turn litmus paper blue, while acids turn it red

4. they have low concentration of [H+] and high concentration of [OH-]

knowing these characteristics, we can determine that D is not bases.