पानी की अस्थायी कठोरता (temporary hardness) को निम्नलिखित में से किस सरल विधि द्वारा प्रभावी रूप से दूर किया जा सकता है?

Which chemical is commonly added to municipal water to kill bacteria?

What primary function does Alum (Potash Alum) serve in the water purification process?

Which one of the following methods is used to remove permanent hardness of water?