All questions and answers from the Living Science Book of Class 8 Science Chapter 15 are provided here for you for free. Explain the primary process variables for each step of the electroplating process. may be the current is so weak that it does not heat the filament of the bulb allowing it to glow. To predict the products of the electrolysis of water based on the chemical ... Use a diagram to illustrate the movement of ions in electroplating. (iii) Food kept in iron cans gets spoilt because of reaction with iron. Do you agree? Record your observations in Table 14.1. Electroplating is the process of plating one metal onto another by hydrolysis, most commonly for decorative purposes or to prevent corrosion of a metal. of this page. Printable Practice worksheets for Class 1 to Class 12 are available on StudiesToday for free download in pdf format for all students. Complete What is Electroplating and How is it Done? [2 Marks] SECTION –B 9. You will also love the ad-free experience on Meritnation’s Living Science 2019 2020 Solutions. Chemical Effects of Electric Current. Stainless steel revolutionised eating after centuries of a bad taste in the mouth by Mark Miodownik. 1. Free Science Class 8 Notes, Class 8 Scince Syllabus, CBSE Class Notes and Study Material, from the latest edition of CBSE (NCERT) books, Solutions and Question Answers. Class 8 Video | EduRev pdf from
Value Points/Expected Answer Marks Distribution Total Marks I.1. How will you carry out electroplating of copper in the laboratory? Ans: Mercury is a metal which is liquid at room temperature. CLASS: VIII SUBJECT: SCIENCE Q.No. However, Fe Ni alloys can be electroplated to form very soft magnetic materials with extensive uses in magnetic and electronic applications at microscale, such as transformers, inductors, and electromagnets. Can you see small bubbles of gases coming out from the water near the nails? Best example of electroplating can be seen on artificial jewellery. Dec 20, 2020 - What is Electroplating and How is it Done? [3 Marks] Class 8 Video | EduRev notes & Videos, you can search for the same too. Electroplating is basically the process of plating a metal onto the other by hydrolysis mostly to prevent corrosion of metal or for decorative purposes. ... designation A or B trivalent chromates are normally used for Grade 5 or Class 8.8 fasteners. Protection of the surface of bases metals which corrode for e.g., iron is plated with chromium. [2 Marks] 8. Ans: The rate of the flow of charge is called an electric current. will not be affordable if made of chromium entirely. Cu+2 move towards cathode to gain electron and neutralize as cu and form layer over iron. It consists of mercury atoms and no ions are present. A battery is commonly used to furnish the electricity for the process. A materials scientist extolls the virtues of electroplating. It gets deposited on the(a) anode(b) cathode(c) half on the anode and half on the cathode(d) sides of the containerAnswer:(b), Question 5.Distilled water is a(a) conductor(b) insulator(c) semi-conductor(d) semi-insulatorAnswer:(b), Question 6.A cell is an example of conversion of(a) magnetic energy into chemical energy(b) electrical energy into chemical energy(c) chemical energy into electrical energy(d) chemical energy into magnetic energyAnswer:(c), Question 7.Which one of the following is a weak electrolyte ? Post-test (10 min.) 1. The object (iron spoon) to be electroplated is made cathode (–ve electrode). The process uses an electric current to reduce dissolved metal cations to develop a lean coherent metal coating on the electrode. Repeat the activity with other liquids such as tap water, vegetable oil, milk, honey. Conducting properties of liquid cannot be compared in this manner. There are also specific types of electroplating such as copper plating, silver plating, and chromium plating. The articles to be plated should be cleaned throughly to remove dust, grease or any deposit on it. OBSERVATIONS Data Table 1. NCERT Exemplar Class 8 Science is very important resource for students preparing for VIII Board Examination. Electrolysis is a method that uses a DC to drive a non-spontaneous chemical reaction. The experimental set-up for electroplating copper on an iron spoon is shown in Fig. The object (iron spoon) to be electroplated is made cathode (–ve electrode). Your email address will not be published. What will be the nature of – (i) plate A (ii) plate B (iii) the solution. The bulb does not glow in … Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell.The voltage that is needed for electrolysis to occur is called the decomposition potential. Hence it is not an electrolyte. Soln: i) In plate A- Pure copper Define Electroplating and understand it using an activity. NCERT Solutions for Class 8 Science Chapter 14 – 1 Mark Questions and Answers. You can download Free What is Electroplating and How is it Done? Class 8 What is Electroplating and How is it Done? (d) Electroplating of _____ is done on objects like water taps and cycle bell to give them a shiny appearance. Class 8 Video | EduRev video for Class 8 is made by best teachers who have written some of the best
Figure 12.7. As C u 2 + ion is positively charged, it moves towards the negative terminal i.e. Electroplating, process of coating with metal by means of an electric current. It is analogous to a galvanic gll acting in reverse. Cyanide Plating The silver bar furnishes the silver ions that are reduced onto the surface of the teapot. Observe the circuit given in Fig. Electroplating process starts with carefully cleaning the fastener surface in alkaline detergent type solutions. A cell consists of two electrodes (conductors), usually made of metal, which are held apart from one another. Explain why plastic containers are favoured for storing food. Using electricity, you can coat the metal of one electrode with the metal of the other with an electroplating process, also known as electrochemistry! Class 8 Video | EduRev search giving you solved answers for the same. 4.8.5 Covering Power and Throwing Power. Class 8 Video | EduRev is made by best teachers of Class 8. Explain why plastic containers are favoured for storing food. Instead of taking the trouble of electroplating metals with chromium for making car parts, taps, cycle parts, etc., why are these objects not made of chromium itself? Which of these do you think uses less electrical energy—electric bulb or LED? 4.8.2 Current Density, pH, Temperature and Conductivity. Short Q&A: Q1: Differentiate between good conductors and bad conductors of electricity. Electroplating uses a form of electrolysis in which the electrodes play a bigger role than just conducting the current.. EXPLORE THE MANY BENEFITS THAT ELECTROPLATING CAN PROVIDE FOR YOUR BUSINESS. Class 8 Science Chapter 14 Chemical Effects of Electric Current . In an acid type bath, the solution is made of 150 – 200 gm of copper sulfate and 25 – 35 gm of sulfuric acid per 1000 cc of solution.Deposit obtained is thick and rough requiring polishing. Define electrolysis. NCERT Exemplar Class 8 Science Unit 14 Chemical Effects of Electric Current Chemical Effects of Electric Current Class 8 Extra Questions HOTS. Boojho set up this circuit for purification of copper. This video is highly rated by Class 8 students and has been viewed 903 times. Read more about the Applications of Electrolysis for IIT JEE (Main and Advanced) at Vedantu.com. Explain the electroplating of copper on an iron spoon. The apparatus is shown in the figure given below. Question from very important topics are covered by NCERT Exemplar Class 8.You also get idea about the type of questions and method to answer in your Class 8th examination. Top Electroplating is the process of depositing a thin film of one metal over another metal by passing electric current through an electrolyte. The lesson covers the complete explanation of class 8 Chapter 14 Chemical Effects of Electric Currents . The teapot acts as the cathode and a bar of silver acts as the anode. What is electroplating? In this article we will talk in detail about electroplating with some demonstrations and uses of electroplating. thumb_up Like (2) visibility Views (2.2K) Science . (ii) Gold or silver is electroplated on jewellery made out of a cheaper metal to make it look attractive. Prachi Chugh. It is one of the most common applications of chemical effects of electric current. This process called electroplating continues until the iron spoon gets coated with copper. Class 8 Video | EduRev for Class 8, the answers and examples explain the meaning
The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating. A thin sheet of pure copper is made anode (+ve electrode).An acidified solution of copper sulphate is used as the electrolytic solution. 4.8.1 Plating Solution Make-up and Analysis Techniques. Thus, iron spoon gets plated with copper. Gradually, a layer of copper builds up on the plate. 4.8.6 Process Monitoring It is an expensive process. Electroplating is done in industries to have an anti-reactive coating on the parts of machines so that they do not react with the raw material, to have an anti-corrosive coating for the machines so that they do not get corroded, and a heat-resistive coating for parts like boilers to … Ans: Solid copper sulphate does not contain any free electrons or ions to conduct electricity. Class-VIII . What is electroplating and its uses - Electroplating is a process that uses an electric current to reduce dissolved metal cations so that they form a thin coherent metal coating on an electrode. 4. Ans: Chromium is very expensive. Use plating artificial jewellery with gold. Electroplating is the application of electrolytic cells in which a thin layer of metal is deposited onto an electrically conductive surface. Differentiate between conductors and insulators. 3. NCERT Solutions for Class 8 Science Chapter 14 – 3 Mark Questions and Answers. It is important to remind learners that circuit diagrams are just schematics of a circuit. Draw a circuit diagram showing a dry cell connected to a bulb through a switch. What is electric current? Liquid B is a better conductor than liquid A. ... Q17: Explain the process of electroplating… All Living Science 2019 2020 Solutions for class Class 8 Science are prepared by experts and are 100% accurate. NCERT Exemplar for Class 8 Science Chapter 14 Chemical Effects of Electric current 20. of chapter in the best manner. Electroplating. Explain the process of purification. So, go through the entire page & read it thoroughly for more clarification. Answer: Class 8 Video | EduRev ppt and other Class 8 slides as well. Copper goes into solution at the anode as it is plated at the cathode. This experiment shows that an electric current can bring about a chemical change. It has gotten 903 views and also has 4.7 rating. Observe the circuit given in Fig. [2 Marks] 10. how_to_reg Follow . Prevalence of Cyanide Electroplating Facilities with Class I Violations 16 14 12 10 8 6 4 2 0 02-03 03-04 04-05 05-06 Fiscal Year No. Class 8 Video | EduRev chapter (including extra questions, long questions, short questions) can be found
Class 8: Chemical Effect Of Electric Current: Living Science. want What is Electroplating and How is it Done? NCERT Exemplar Class 8 Science Chapter 14 is a free resource which is very helpful while preparing for your upcoming board examination. (iv) Zinc is electroplated on iron used to make bridges and automobiles. There is no scarcity of C u atoms because the copper atoms go into the solution from the positive terminal i.e. Ans: Uses of electroplating: (i) Chromium is a shiny metal that does not corrode and resists scratches. 2. What happens when electricity is passed through tap water? For copper plating, two types of electrolytic baths are used.. books of Class 8. Over the years, we have developed and perfected our industrial electroplating processes that make use of various metals and metal alloys to achieve the desired result for our customers. Here we have provided NCERT Exemplar Problems Solutions along with NCERT Exemplar Problems Class 8.. This happens because the when current is passed, the K+ ions are attracted to the metal sheet. Conduct copper plating activity. In the process of electroplating the object to be electroplated is used as Cathode and the metal which is used for coating is used as Anode. Through diagram represent movement of ions during electrolysis. Question 1. Draw a circuit diagram showing a dry cell connected to a bulb through a switch. Ans: Zinc is electroplated on iron to prevent it from rusting. Plating metal may be transferred to conductive surfaces (metals) or to nonconductive surfaces (plastics, wood, leather) after the latter have been rendered conductive by such processes as coating with graphite, Ans: When an electrolyte is dissolved in water, it breaks up into cations (positively-charged ions) and anions (negatively-charged ions). Ans: A substance which conducts electricity in the liquid state or when dissolved in water and breaks up chemically during the process is called an electrolyte. Take out the ends of the tester from the lemon juice, dip them in water and then wipe them dry. 4.8.3 Cathode Efficiency and Anode Efficiency. It includes many interesting as well as important chapters to expand the horizons of knowledge. Give two practical examples from daily life which proves rectilinear propagation of light. Electrolytes conduct current at a slow rate than metals. consumption. Electrolyte is the solution of soluble salt of metal to be deposited. Most liquids that conduct electricity are solutions of …………, ………. The writing appears on the paper. Take water in a beaker and add to it a little salt or a few drops of sulphuric acid to make it conducting. Write one important application of electrolysis in our daily life. What is this phenomenon called? When electric current is passed through the solution, the cations move towards the cathode (negatively-charged electrode) and the anions move towards anode (positively-charged electrode). All Living Science Solutions for class Class 8 Science are prepared by experts and are 100% accurate. Why is a layer of zinc coated over iron? What do you think will happen now? To understand how the laws of attraction govern the formation of ions and molecules 2. The process of depositing a layer of any desired metal on another material by means of electricity is called electroplating. On the diagram above (Figure 2) indicate the direction of electron flow in both wires, and label the anode and cathode on both the battery and the electrolytic cell. Metal Extraction (Electrometallurgy) Electrometallurgy is the process of electrolysis for extracting … Iron rod made as cathode and copper rod as anode and dipped into copper sulphate electrolyte. Ans: Putting out a fire in an electrical appliance by pouring water on it can be dangerous as water conducts electricity and people who come in contact with the water can get electric shocks. Do you think it is an electrolyte? 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