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Chemical Effects Of Electric Current

Question

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How can you prepare an electric pen?

Solution

The steps to make an electric pen is mentioned below:

1. Take a filter paper and soak it into potassiumiodide and starch solution.
2. Spread the filter paper on a metal sheet.
3. Now join two connecting wires to the terminals of battery.
4. Attach the wire connected at positive end to the plate.
5. Now, write on the sheet attached to the negative terminal of the battery. On the segments where you are writing, blue color will appear.

This happen due to electrolysis of potassium iodide solution which produces iodine. Iodine on reaction with starch produce ink of blue colour.

Some More Questions From Chemical Effects of Electric Current Chapter

In case of fire, before the firemen use the water hoses, they shut off the main electrical supply for the area. Explain why they do this.

A child staying in the coastal region tests the drinking water and also the seawater with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?

Is it safe for the electrician to carry out electrical repairs outdoors during heavy downpour? Explain.

Paheli had heard that rainwater is as good as distilled water. So she collected some rainwater in a clean glass tumbler and tested it using a tester. To her surprise she found that the compass needle showed deflection. What could be the reasons?

Prepare a list of objects around you that are electroplated.

The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?

What are conductors?

What are insulators?

Name one conductor.

Name one insulator.

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