1. Do lemon juice or vinegar conduct electricity?
2. What type of effect of current do the deposits of metals on electrodes show?
3. Name the three different effects of electric current.
4. Name the scientist who had first shown that bubbles of oxygen and hydrogen were produced during electrolysis of water?
5. When electric current is passed through conducting solution, there is a change in the colour of the solution. What does it indicate?
Q1. Give reason why
A. Bubbles are produced during electrolysis of water.
B. Electrodes should be good conductors of electricity.
C. Graphite despite being a non metal can be used as an electrode.
Q2. Answer the following
A. Define electrodes.
B. An electric current is passed through a conducting solution. List any three possible observations.
C. What happens when an electric current is passed through a cut potato for a considerable time?
1.Name the gas deposited on the negative electrode during electrolysis of water.
2.How can we prepare electrodes from discarded cells?
3.During electrolysis of water oxygen bubbles are formed near which electrode?
Answers
1. Do lemon juice or vinegar conduct electricity?
Lemon juice has citric acid in it. When lemon juice is added to water, the acid dissociates into anions and cations which are charged. Hence they can conduct electricity as these charged particles are able to flow inside the acid. Even though lemon, as well as vinegar, are weak conductors of electricity
2. What type of effect of current do the deposits of metals on electrodes show?
The passage of an electric current through a conducting solution causes chemical reactions as a result, bubbles of gas are formed, deposits of metal are seen on electrodes, or changes in the color of the solution, may occur. These are some of the chemical effects of electric current.
3. Name the three different effects of electric current.
eating effect, magnetic effect, and chemical effect.
4. Name the scientist who had first shown that bubbles of oxygen and hydrogen were produced during the electrolysis of water?
Dmitry Lachinov in 1888.
5. When an electric current is passed through conducting solution, there is a change in the color of the solution. What does it indicate?
This is a chemical effect of electric current. A chemical reaction occurs when an electric current is used to conduct a solution. This results in a color shift, which is due to the chemical effect of electric current.
A. Bubbles are produced during the electrolysis of water.
Electrolysis of water produces hydrogen bubbles with size distribution depending on different factors. The water near the cathode gets supersaturated with hydrogen, and hence the release of hydrogen at the electrode nucleates bubble at the electrode surface at several nucleation sites.
B. Electrodes should be good conductors of electricity.
Electrodes are a special class of electrical conductors. Because they are able to contact a non-metallic part of a circuit, and so complete it. They come in various shapes and sizes, and we use them to connect to electrolytes and semiconductors. They can also send electrons in a vacuum, or through the air.
Q2. Answer the following
A. Define electrodes.
a conductor through which electricity enters or leaves an object, substance, or region.
B. An electric current is passed through a conducting solution. List any three possible observations.
The conducting solution has free ions available which conduct electricity. Deposits of metal may be seen on electrodes. Bubbles of gas may be formed on the electrodes. The solution may get heated.
C. What happens when an electric current is passed through a cut potato for a considerable time?
A greenish-blue spot is formed around the positive electrode. The chemical effect of the electric current is involved in this process.
1. Name the gas deposited on the negative electrode during electrolysis of water.
hydrogen ions H +(aq) (from the water) are discharged at the negative electrode as hydrogen gas, H 2(g).
2. How can we prepare electrodes from discarded cells?
Pour a cupful of water into a glass/ plastic bowl. Add a teaspoonful of salt or a few drops of lemon juice to the water to make it more conducive. Now immerse the electrodes in this solution. Make sure that the metal caps of the carbon rods are outside the water.
3. During electrolysis of water oxygen bubbles are formed near which electrode?
Oxygen will collect at the positively charged electrode (anode)