Question

Which of the following ion is responsible for the temporary hardness of water?  

Options

• \[\ce{SO_4^2-}\]

• \[\ce{HCO_3^-}\]

• \[\ce{NO_3^-}\]

• \[\ce{Cl^-}\]

Answer 1

\[\ce{HCO_3^-}\]

Explanation:

\[\ce{HCO_3^-}\] is the primary cause of water temporarily becoming hard.