Author: Dr. Vikas Jasrotia

Electrochemistry Important Questions – Class 12  Electrochemistry Important Questions Que 1. Why does a cell stop working after some time? Que 2. What is the electrolyte used in a dry cell? Que 3. Why can a lead storage cell be recharged? Que 4. Why does a dry cell become dead after a long time even if it has not been used? Que 5. Mention the reaction occurring at (i) anode and (ii) cathode during the working of mercury cell. Que 6. Name any two metals which can be used for the cathodic protection of iron? Que 7. Why is it…

(Answers) Class 10 Chemical Reactions and Equations Test – 1 (Answers) Class 10 Chemical Reactions and Equations Ans 1. The word equation for the reaction is: Iron + Water → Ferric oxide + Hydrogen The symbol equation for the same reaction is: Fe + H2O → Fe2O3 + H2 ­ The balancing of the equation is done in the following steps: Step I. Let us count the number of atoms of all the elements in the reactants and products on both sides of the equation. Element No. of atoms of reactants (L.H.S.) No. of atoms of products (R.H.S.) Fe 1…

Class 10 Chemical Reactions and Equations Test – 1 Class 10 Chemical Reactions and Equations Que 1. Write a balanced chemical equation for the following (using different steps) (i) Iron reacts with water (steam) to form the ferric oxide and liberate hydrogen gas. (ii) When potassium chlorate (KClO3) is heated in the presence of a manganese dioxide catalyst, it decomposes to form potassium chloride and oxygen gas. Que 2. Identify the following reaction type in which: (i) Carbon monoxide reacts with oxygen to form carbon dioxide (ii) Ferrous sulphate is heated strongly Que 3. When an electric current is passed…

Class 12 Electrochemistry Test Paper – 2 (Solution) Class 12 Electrochemistry Test Paper – 2 (Solution) Ans 1. The arrangement of metals and ions in increasing order of their electrode potential values is called electrochemical series. The reduction half-reaction for which the reduction potential is lower than the other will act as an anode and one with greater value will act as a cathode. A reverse reaction will not occur. Ans 2. Electrochemical cells are used for determining the a) pH of solutions b) Solubility product and equilibrium constant c) In potentiometric titrations Ans 3. (i) Standard electrode potential and…

Class 12 Electrochemistry Test Paper – 2 Class 12 Electrochemistry Test Paper Que 1. What is an electrochemical series? How does it predict the feasibility of a specific redox reaction? Que 2. Give some uses of electrochemical cells? Que 3. How is the standard electrode potential of a cell related to: (a) Equilibrium constant? (b) Gibbs free energy change Que 4. What are the factors on which the conductivity of an electrolyte depends? Que 5. State Kohlrausch law. Write the reaction which occurs at the electrode of the hydrogen-oxygen fuel cell. Que 6. A current of 2A is passed for…

Chapter Electrochemistry Test Paper – 1 (Solutions) Chapter Electrochemistry Test Paper (Solutions) Ans 1.  Ans 2. Ans 3. (A). Any redox reaction would occur spontaneously, if the cell emf is positive. Ans 4. (C).  2H2O → 2H2(g) + O2(g) 2x                           x ∴ 3x = 0.168 ∴ x = 0.056L VH2= 2x = 0.112L,   VO2= x = 0.056L 11.2L of H2 at STP = 1F 0.112L of H2 at STP = 0.01F 0.056L of O2 at STP = 0.01F ∴ The amount of electricity passed = 0.01F = 965C Ans 5. (C). The type of electrode Pb | PbSO4(s) | H2SO4 used in acid…

Chapter Electrochemistry Test Paper – 1 Chapter Electrochemistry Test Paper Que 1. Calculate the volume of gas liberated at anode at NTP from the electrolysis of CuSO4 solution by a current of 2 amperes passed for 10 minutes. (A) 0.0696 litre (B) 0.0211 litre (C) 0.0727 litre (D) 0.5312 litre Que 2. The conductivity of a solution may be directly proportional to the total concentration of the charge carriers (ions) present in it in many cases. Find the percent decreases in conductivity (k) of a weak monoacidic base BOH solution when its 0.1 M solution is diluted to double its…

Solutions Chemistry Class 12 Chapter Solution Test Paper – 2 Solutions Class 12 Chapter Solution Test Paper Ans 1. Ans 2. The solute is 50% dissociated Ans 3. Ans 4. Ans 5. According to Raoult’s law,  (p0 – p) / p0 = (w × M) / (m × W) p0 → is Vapour pressure of pure water p → is vapour pressure of the solvent w → is weight of solute m → is the molecular weight of solute W → is the molecular weight of solvent (32 – 31.84) / 32 = (10 × 18) / (m × 200) m =…

Class 12 Chapter Solution Test Paper Chemistry Class 12 Chapter Solution Test Paper – 2 Class 12 Chapter Solution Test Paper Que 1. A 10% solution of urea is isotonic with a 20% solution of ‘x’ at the same temperature. Calculate the molecular weight of x. Que 2. In the determination of the molar mass of A + B – using a colligative property, what may be the value of van’t Hoff factor if the solute is 50% dissociated? Que 3. The density of water in a lake is 1.25 g mL–1 and one kg of this water contains 92g…

Answers Chapter Solutions Test Paper – 1 Answers Chapter Solutions Test Paper Ans 1. (C). Explanation: Let, mass of solution = 100 g Mass of nitric acid in the solution = 68 g Density of the solution = 1.504 g mL–1 Volume of the solution = 100 g/1.504 g/ml = 66.49 mL =  66.49/ 1000L = 0.066 L Amount of nitric acid in solution = 68g / Molar mass of nitric acid = 68 g / 63g/mol = 1.079 mol Then, molarity of nitric acid solution = 1.079 / 0.066 = 16.23 mol/L Ans 2. (B). Explanation: Level of contamination =…