What are weak and strong electrolytes?

Electrolytes are substances which, when dissolved in water, break up into cations (positively charged ions) and anions (negatively charged ions). 

Weak electrolytes partially dissociate into ions in solution and are weak conductors of electricity. Types of weak electrolytes include weak acids and bases.

Examples of weak electrolytes include acetic acid and mercury(II) chloride.

Strong electrolytes dissociate into ions almost completely in a solution. These ions are good conductors of electric current in the solution.

Examples of strong electrolytes are acid: Hydrochloric Acid (HCl), Base: Sodium Hydroxide (NaOH), Salt: Sodium Chloride (NaCl).