Question

The elements whose oxides can turn phenolphthalein solution pink are ______.

Options

• Na and K

• K and C

• Na and S

• K and P

Answer 1

The elements whose oxides can turn phenolphthalein solution pink are Na and K.

Explanation:

Sodium (Na) and potassium (K) are metals that react with oxygen to form basic oxides. When these metallic oxides dissolve in water, they produce strong bases (alkalis) like sodium hydroxide and potassium hydroxide. Phenolphthalein is a chemical indicator that turns bright pink specifically in the presence of basic solutions.