Salt, as well as any other soluble substance, dissolves quicker in hot water because heat makes the water molecules move faster, creating more space between them. This extra space means the salt molecules more readily make contact with the water molecules, binding to them and creating a solution.
Salt dissolves in water because the water molecule has a negative and a positive end. Chloride ions in salt are negatively charged, while the sodium ions carry a positive charge. The charged ends of the water molecule attract the ions in the salt, breaking the salt’s crystalline formation.
When water is heated, the water molecules move quicker and farther apart. This creates more space between the water molecules, so the salt molecules can bond to them more readily. Stirring also speeds up the process by bringing the salt and water molecules into contact with each other.