how to know if an acid is weak or strong , i simply don't understand the idea of dissolving or not dissolving completely in water ,,,,
2 answers
The strength of an acid depends upon how completely it dissociates into hydrogen ions and negative ions, not how fully it dissolves.
It relatively easy to remember the common strong acids. HCl, HBr, HI, HClO4, HClO3, H2SO4(the first H ion but not the second), HNO3. There are one or two others but these are the common ones; the other acids are weak.