The passage of an electric current through a solution causes a chemical effect.

Explanation:
When an electric current is passed through a solution, it can cause various effects. These effects are due to the movement of charged particles (ions) within the solution. The chemical effect of an electric current refers to the chemical changes that occur at the electrodes (the points where the current enters and leaves the solution).

Electrolysis:
When an electric current is passed through a solution, it can lead to a process called electrolysis. Electrolysis is the chemical decomposition of a compound into its constituent elements or ions using electricity. This process occurs at the electrodes.

Electrodes:
The electrodes used in electrolysis are typically made of a conductive material such as metal or graphite. There are two types of electrodes: the anode and the cathode. The anode is the positively charged electrode, where oxidation (loss of electrons) occurs. The cathode is the negatively charged electrode, where reduction (gain of electrons) occurs.

Chemical Reactions:
During electrolysis, chemical reactions occur at the electrodes. These reactions can vary depending on the nature of the solution and the ions present. For example, if the solution contains an ionic compound such as sodium chloride (NaCl), the compound will dissociate into Na+ and Cl- ions. At the anode, chloride ions (Cl-) will be oxidized to chlorine gas (Cl2), while at the cathode, sodium ions (Na+) will be reduced to sodium metal (Na).

Examples of Chemical Effects:
The chemical effects of an electric current can be observed in various practical applications. Some examples include:

1. Electroplating: Electroplating is a process in which a metal object is coated with a thin layer of another metal using electrolysis. This is achieved by passing an electric current through a solution containing ions of the metal to be plated. For example, silverware can be electroplated with a layer of gold.

2. Electrorefining: Electrorefining is the process of purifying metals using electrolysis. It is commonly used in the extraction and refining of metals such as copper and zinc. The impure metal is dissolved in a solution, and then an electric current is passed through the solution to deposit the pure metal on the cathode.

3. Electrolytic cells: Electrolytic cells are devices that use an electric current to drive non-spontaneous chemical reactions. These cells are used in various industries for processes such as water splitting, metal extraction, and production of chemicals.

In conclusion, the passage of an electric current through a solution causes a chemical effect, which leads to various chemical reactions and processes such as electrolysis, electroplating, and electrorefining.