PLEASE HELP ME I DONT KNOW WHAT TO DO

Write a net ionic equation to show that hydrofluoric acid, behaves as an acid in water.

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?

Assuming complete dissociation of the solute, how many grams of kno3 must be added to 275 ml of water to produce a solution that freezes at -14.5 c? the freezing point for pure water is 0.0 c and k_f is equal to 1.86 c/m