Question

Arrange NaOH solution, blood, lemon juice in increasing order of pH.

Answer 1

The pH scale measures the concentration of ${\mathrm{H}}^{+}$ions, it expresses the acidity and basicity of a substance.

Acid is a substance ( molecule or ion) that has a tendency to donate ${\mathrm{H}}^{+}$ions, and its pH value lies between 0-7.

The base is a substance (molecule or ion) that has a tendency to accept ${\mathrm{H}}^{+}$ions and donate ${\mathrm{OH}}^{-}$ions, and its pH value lies between 7-14.

Since lemon juice has a pH level of 2.2 - 2.4, blood has a pH level of approx 7, NaOH solution has a pH level of 14.

The order is as follows:

Lemon juice < blood < NaOH solution.