Chemical Effects of Electric Current Flashcards
Tester
Is a simple instrument used to check the flow of electric current. It is attached to the terminal of the circuit, if the bulb attached to the tester glows, it confirms the flow of current.
Electrolysis
The decomposition of water into oxygen & hydrogen gas when current passes through it is called electrolysis.
Electroplating
It is process of depositing a layer of any desired metal on another material is called electroplating.
What is LED? What are the uses, advantages & structure.
LED=(Light emitting diode)
STRUCTURE- I has two wires (called leads) connected to the LED. One of them is slightly longer than the other, the longer lead is attached to the positive terminal of the battery and the shorter side is attached to the negative terminal of battery.
USES- Used in traffic lights, Used for lightning & A cluster of white LED is grouped together to form a LED light source.
ADVANTAGES- Uses less electricity. It has longer lifetime than bulbs and florescent tubes.
How can a magnetic compass used as a tester?
When electric current is passing through a wire, the needle of the compass deflects. The needle deflects even if there is small amount of current passing through a wire, so it can be used as a tester using the magnetic effect of electric current.
2 devices used to detect week current
LED & Magnetic compass
Tap water is a good conductor of electricity. Why?
The water we get from taps, hand pumps, wells and ponds is not pure. It contains several salts. Water also has mineral salts in it naturally. So tap water is a good conducted of electricity.
Chemical effects of electric current
When current passes through conducting solution, some chemical reactions occur in the solution. This is called the chemical effect of electric current.
Gas bubbles are formed
Desired metal can be seen on the electrodes
Colour of the solution may change
Explain electrolysis of water
When electric current passes through water it splits it into H+ & OH iodes. Hydrogen gas bubble are formed on the electrode connected to negative terminal of the battery 🔋. Oxygen gas bubble are formed on the electrode connected to negative terminal of the battery 🔋. William Nicholson is was the first person to discover electrolysis of water.
Process of Electroplating
When electric current passes through Copper Sulphate solution it dissociates into Copper & Sulphate.
The free copper is drawn to the electrode connected to the negative terminal and gets deposited.
The other electrode, the copper plate, an equal amount of copper get dissolved in the solution.
The copper lost in the solution is restored and this process continues.
Why is chromium deposited on other objects.
Mention 4 appliances
Chromium has a shiny appearance.
It does not corrode. It resist scratches.
Chromium is expensive and it is economical to make the whole object out of chromium, so the object is deposited with chromium.
APPLIANCES- Gas burners, Wheel rims, Water taps & Car parts.
Iron cans are electroplated with tin. Give reason-
Tin cans are made by electroplating tin onto iron because tin is less reactive than iron and separates iron from food and protects it from getting spoilt.
zinc is deposited on iron bridges. why ?
automobiles and bridges are made out of iron for strength. iron tends to corrode and rust. to prevent the corrosion & formation of rust , zinc is deposited on iron bridges.
