Description : Using the electrochemical series, how can I explain why manufacturers coat steel nails with zinc rather than copper?
Last Answer : Because the use of zinc is…......... Nah you do the work , or its called cheating :P
Description : During electrolysis of aqeous solution of NaCl, there are two type of anions are present Cl- and –OH, Cl- is discharged first than –OH,although it is present below Cl- in electrochemical series. Give reason.
Last Answer : Ans: During this electrolysis process Chloride ions come from NaCl, which is a strong electrolyte and ionize to large extent so concentration of chloride ions in solution will be high. ... chloride ions it is first discharged despite of its presence above than hydroxyl in electrochemical series.
Description : Why cation present below in electrochemical series can discharge before the elements present above them in an electrochemical cell?
Last Answer : Ans: This is because their ability to be reduced (reduction potential) is more than the cation present above them in electrochemical series. So they take electrons before the other cations and get discharged.
Description : Though tin occurs lower than iron in the electrochemical series, yet it is coated on steel for corrosion protection, because of its (A) Lower cost (B) Abundant availability (C) Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry (D) None of these
Last Answer : (C) Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry
Description : Among the following, which is always found in free-state in nature? (1) Gold (2) Silver (3) Sodium (4) Copper
Last Answer : (1) Gold Explanation: Gold is the least reactive in the reactivity series. Since it does not react with other elements, it is found in a free form. Only gold, silver, copper and the ... occur in nature in larger amounts. Nonmetallic elements occurring in the native state include carbon and sulfur.
Last Answer : Gold
Description : Which of the following is always found in a free state in nature? (a) Gold (b) Silver (c) Sodium (d) Copper
Last Answer : Ans:(a)
Description : Two half-reactions of an electrochemical cell are given below : MnO-4 (aq) + 8H+ (aq) + 5e- → Mn2+ (aq) + 4H2O (I), E° = 1.51 V Sn2+ (aq) → Sn4+ (aq) + 2e- ... the redox equation from the standard potential of the cell and predict if the reaction is reactant favoured or product favoured. -Chemistry
Last Answer : The reactions can be represented at anode and at cathode in the following ways : At anode (oxidation) : Sn2+ → = Sn4+ (aq) + 2e- ] 5 E° = + 0.15 V At cathode (reduction) : MnO-4(aq) + 8H+ ... = E°cathode - E°anode = 1.51 - 0.15 = + 1.36 V ∴ Positive value of E°cell favours formation of product.
Description : Two half-reactions of an electrochemical cell are given below : MnO-4 (aq) + 8H+ (aq) + 5e- → Mn2+ (aq) + 4H2O (I), E° = 1.51 V Sn2+ (aq) → Sn4+ (aq) + ... -reactions and calculate the cell potential from the standard potentials and predict if the reaction is reactant or product favoured. -Chemistry
Last Answer : The reactions can be represented at anode and at cathode in the following ways : At anode (oxidation) : Sn2+ → Sn4+ (aq) + 2e- ] 5 E° = + 0.15 V Af cathode (reduction) : MnO-4(aq) + 8H+ ( ... = E°cathode - E°anode = 1.51 - 0.15 = + 1.36 V ∴ Positive value of E°cell favours formation of product.
Description : Silver gets corroded due to ______ in air. (1) Oxygen (2) Hydrogen Sulphide (3) Carbon dioxide (4) Nitrogen
Last Answer : (2) Hydrogen Sulphide Explanation: Silver is a fairly stable metal and under normal circumstances does not corrode quickly. However, it is particularly susceptible to the effects of the sulfide ... atmosphere, especially in marine environment, and readily forms a surface tarnish of silver sulphide.
Description : Silver gets corroded due to ___ in air. (1) Oxygen (2) Hydrogen Sulphide (3) Carbon dioxide (4) Nitrogen
Last Answer : Hydrogen Sulphide
Description : Copper and carbon wires are connected in series and the combined resistor is kept at `0^(@)C`. Assuming the combined resistance does not vary with tem
Last Answer : Copper and carbon wires are connected in series and the combined resistor is kept at `0^(@)C`. Assuming the combined ... C)` A. 4 B. 8 C. 6 D. 2
Description : Write the molecular formulae of: 1. Copper oxide 2. Iron (III) chloride 3. Sodium hydroxide 4. Iron (II) sulphide 5. Lead (II) oxide 6. Hydrogen nitrate (nitric ... Hydrogen sulphate (sulphuric acid) 8. Calcium hydroxide 9. Magnesium carbonate 10.Ammonium carbonate
Last Answer : 1. Copper oxide - CuO 2. Iron (III) chloride - FeCl3 3. Sodium hydroxide - NaOH 4. Iron (II) sulphide - FeS 5. Lead (II) oxide - PbO 6. Hydrogen nitrate (nitric acid) - HNO3 7. ... ) - H2SO4 8. Calcium hydroxide - Ca(OH)2 9. Magnesium carbonate - MgCO3 10.Ammonium carbonate - (NH4)2CO3
Description : Pick out the correct statement. (A) Stainless steel is nothing but chromium coated steel (B) Hardening of a soft metal can be done by alloying it with another metal or non-metal (C) ... its temporary distortion under the action of applied stress (D) Rusting of iron is not electrochemical in nature
Last Answer : (B) Hardening of a soft metal can be done by alloying it with another metal or non-metal
Description : The cathode in an electrochemical cell always carries (A) Negative charge (B) Positive charge (C) Zero charge (D) Positive or negative charge depending upon the nature of the cell
Last Answer : (A) Negative charge
Description : Electrometallurgical methods of metal extraction is normally used for those metals (A) Whose oxide/ore is not reduced by carbon (B) Which fall in the category of alkali & alkaline earth metals (C) Which stands higher in the electrochemical series of the metal (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : Extraction of `Ag` from sulphide ore and removal of unreacted silver bromide from phorographic plate involve complexes:
Last Answer : Extraction of `Ag` from sulphide ore and removal of unreacted silver bromide from phorographic plate involve ... (3))_(2)]^(3-)` respectively
Description : Is platinum found in nature or is it only found combined with other elements in chemical compounds?
Last Answer : Platinum is found in the nature in elemental form.
Description : When elements that are never found free in nature but are always found combined in a compound are the?
Last Answer : These elements are very reactive.
Description : Which one of the following statements is not correct as regard to international resources? (a) Resources which are regulated by international institutions. (b) Resources which lie beyond the territorial ... which are found along the international frontier. (d) Resources which are not yet developed.
Last Answer : (d) Resources which are not yet developed.
Description : Assertion : Froth flatation process is used to concentrate sulphide ores. Reason : There is a difference in the nature of wettibility of different ore
Last Answer : Assertion : Froth flatation process is used to concentrate sulphide ores. Reason : There is a difference ... -1 is false but Statement -2 is true
Description : Statement-1: Auto reduction of ores is used for cinnabar, copper glance and Galena ores Statement-2:The sulphide ores of these metals react with their
Last Answer : Statement-1: Auto reduction of ores is used for cinnabar, copper glance and Galena ores Statement-2: ... Statement-1 is false but Statement -2 is true
Description : The most suitable method for extraction of copper from low grade sulphide ore is
Last Answer : The most suitable method for extraction of copper from low grade sulphide ore is A. Smelting ... process C. Leaching process D. Electrolytic process
Description : (A) Auto reduction of ore is used for the extraction of copper (R ) The sulphide ore of copper reacts with its oxide to the give the metal
Last Answer : (A) Auto reduction of ore is used for the extraction of copper (R ) The sulphide ore of copper reacts ... . If (A) is incorrect but (R ) is correct
Description : The method used for the enrichment of sulphide ores of copper is
Last Answer : The method used for the enrichment of sulphide ores of copper is A. Mangetic Separation B. Froth floatation process C. Electro refining D. Smelting
Description : What are the elements that make up copper sulphide?
Last Answer : Copper sulfide contain copper and sulfur.
Description : Which of the following statements represents the main difference between a relay and a contactor? A. Contactors control current and relays control voltage. B. A relay is series connected and a contactor ... loads than relays. D. Contactors are made from silver and relays are made from copper.
Last Answer : Answer: C
Description : Cinnabar, pyrite and galena are minerals which consist of one or more metals combined with the same element. Which one of the following is the element that is common to all three of these minerals? Is it: w) iron x) copper y) sulfur z) sodium
Last Answer : ANSWER: C-- SULFUR
Description : The chemical reaction between Hydrogen sulphide and iodine to give Hydrogen iodide and sulphur is given below: The oxidizing and reducing agents involved in this redox reaction are: (a) ... and hydrogen sulphide respectively (c) Sulphur and iodine respectively (d) Hydrogen sulphide and sulphur
Last Answer : (b) Iodine and hydrogen sulphide respectively
Description : ‘’India is important to iron and steel producing country in the world yet, we are not able to perform our full potential. Comment on this statement. -Geography
Last Answer : India is the 4th largest producer of crude steel in the world. The challenges faced by this industry are : 1. Coking coal has limited availability and also is costly. 2. The labour has ... need of Steel policy similar to that of National Jute policy and work accordingly to increase the yield.
Description : The chemistry of corrosion of iron is essentially an electrochemical phenomenon. Explain the reactions occurring during the corrosion of iron in the atmosphere. -Chemistry
Last Answer : The mechanism of corrosion is explained on the basis of electrochemical theory. By taking example of rusting of iron, we Refer tothe formation of small electrochemical cells on the surface of iron. The redox reaction involves ... net resultant Redox reaction is 2Fe(s) + O2 (g) + 4H+ → 2Fe2+ + 2H2O
Description : What is Electrochemical Equivalence ?
Last Answer : One ampere conducts an electric current for one second, that is , one coulomb conducts an electric current.
Description : What is Electrochemical Cell ?
Last Answer : Electrochemical cell is a type of cell through which electricity can be generated from chemical energy.
Description : n electrochemical cell which is used as a source of direct electrical current at constant voltage under standard conditions is called a – (1) Power transmittor (2) Battery (3) Uninterrupted power supply (UPS) (4) Generator
Last Answer : (3) Uninterrupted power supply (UPS) Explanation: A Galvanic cell, also known as battery, is an electro-chemical cell that derives electrical energy from spontaneous redox reactions taking place within ... produce direct current. A battery is a set of galvanic cells that are connected in parallel.
Description : The rusting of iron is a/an - (1) physical change (2) electrochemical change (3) electrical change (4) None of the above
Last Answer : (2) electrochemical change Explanation: When iron is exposed to air and moisture, its surface gradually corroded and converted into a brown mass. The rusting of iron is due to the formation of hydrated ion. Rusting is an electro-chemical process.
Description : The deterioration of a metal by an electrochemical process is commonly termed as – (1) Erosion (2) Corrosion (3) Passivation (4) Abrasion
Last Answer : (2) Corrosion Explanation: Corrosion can be defined as the deterioration of materials by chemical processes.
Description : What would happen if salt bridge is not used in electrochemical cell ?
Last Answer : Ans. :- The cell works for short time .After that electrons stop flowing from anode to cathode due to accumulation of +ve ions at anode and no reduction will occur at cathode . The result is that current stops flowing and cell will not work .
Description : What is meant by Electrochemical cell . Why is it called as galvanic cell and Voltaic cell ?
Last Answer : Ans. :- The cell which converts chemical energy into electrical energy . It is called as galvanic cell and Voltaic cell after the name of scientists who first tried to convert chemical energy into electrical energy .
Description : What is the principle of electrochemical cell ?
Last Answer : Ans .:- The cell works on the principle of redox reactions . One of the reactant undergoes oxidation while another undergoes reduction
Description : Which one of the following statements is not correct? A Since voltage depends on concentrations, using standard conditions makes it easier to compare different electrochemical reactions. B We have ... half-reactions are determined by combining the relevant half-cell with a standardised half-cell.
Last Answer : C The direction of a redox reaction can only be determined experimentally.
Description : What is the purpose of the salt bridge in an electrochemical cell? w) It allows ion migration. x) It allows electron flow. y) It prevents ion migration. z) It prevents electron flow.
Last Answer : ANSWER: W -- IT ALLOWS ION MIGRATION
Description : The deterioration of a metal by an electrochemical process is commonly termed as (1) Erosion (2) Corrosion (3) Passivation (4) Abrasion
Last Answer : Corrosion
Description : An electrochemical cell which is used as a source of direct electrical current at constant voltage under standard conditions is called a : (1) Power transmittor (2) Battery (3) Uninterrupted power supply (UPS) (4) Generator
Last Answer : Battery
Description : The rusting of iron is a/an (1) physical change (2) electrochemical change (3) electrical change (4) None of the above
Last Answer : electrochemical change
Description : Name any four factors affecting electrochemical corrosion.
Last Answer : A) Nature of metal: 1) Position of metal in a galvanic series: A metal having higher position in a galvanic series has more chemical reactivity and therefore, it gets attacked by gaseous and ... as a conducting medium and promotes corrosion. e.g:- Rusting of Fe is promoted in humid atmosphere.
Description : Drinks remain hot or cold for a long time in a thermos flask because of the (a) presence of air, which is a bad conductor of heat, in between the double walls (b) silver coating on the inside of the double walls (c) vacuum between the double walls (d) combined effects of (b) and (c)
Last Answer : Ans:(d)
Description : “The story of Ho Chi Minh trail is one way of understanding the nature of war that the Vietnamese fought against US.” Is it true? Comment. OR Write an evaluation of Vietnamese war against the US from the point of a porter on the Ho Chi Minh trail. -SST 10th
Last Answer : Ho Chi Minh trail symbolises how the Vietnamese used their limited resources to great advantage. About 20,000 North Vietnamese troops came to South Vietnam each month on this trail. The ... to destroy this important supply line by intensive bombing failed because they were rebuilt very quickly.
Description : I am broken and apart, all my pieces are in tatters. They lie about unorganized, as if nothing matters. Like humpty dumpty all I want is all my pieces fixed. Yet when you start to help me, your feelings ... I bring anger. To see my original form, you need only look at my chamber. What am I? -Riddles
Last Answer : Jigsaw puzzle
Description : I’m teary-eyed but never cry, silver-tongued, but never lie. double-winged, but never fly, air-cooled, but never dry. What am I? -Riddles
Last Answer : Mercury. The element looks shiny, silver, and is wet. The god Mercury has two wings but only uses them to run.
Description : Which one of the following metals occurs in nature in free state? (1) Gold (2) Sodium (3) Aluminium (4) Copper
Last Answer : (1) Gold Explanation: Gold is found on every continent on Earth, except Antarctica. The largest amounts of gold on Earth are found in the oceans - but it is not yet feasible to extract gold from seawater.