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WIN TECH ACADEMY PRELIMINARY EXAM CHEMISTRY Maximum Marks: 80 Time allowed: Two hours Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during first 15 minutes. This time is to be spent in reading the question paper. The time given at the head of this Paper is the time allowed for writing the answers. Section A is compulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets [ ]. SECTION A (40 Marks) (Attempt all questions from this Section.) Question 1: [15] 1. A student takes Cu, Al, Fe and Zn strips, separately in four test tubes labeled as I, II, III and IV respectively. He adds 10 ml of freshly prepared ferrous sulphate solution to each test tube and observes the colour of the metal residue in each case. He would observe a black residue in the test tubes: (I) and (II) (I) and (III) (II) and (III) (II) and (IV) 2. Which of the following about oxides is correct? a. A basic oxide is an oxide of a non-metal b. Acidic oxides contain ionic bonds c. Amphoteric oxides contain a metal d. Basic oxides are always gases 3. Aqueous lead (II) nitrate can be distinguished from aqueous zinc nitrate by adding any of the following solution in excess, except: a. aqueous potassium chloride b. aqueous sodium sulphate c. dilute sulphuric acid d. sodium hydroxide solution 4. The ratio between the volumes occupied by 4.4 grams of carbon dioxide and 2 grams of hydrogen gas is: a. 2.2 : 1 b. 1 : 2.2 c. 1 : 10 d. 10 : 1 5. Assertion (A): Alkali metals do not form dipositive ions. Reason (R): After loss of one electron alkali metals achieve stable electronic configuration of noble gases. a. Both A and R are true and R is the correct explanation of A b. Both A and are true but R is not the correct explanation of A c. A is true but R is false d. A is false but R is true 6. A compound P is heated in a test tube with sodium hydroxide solution. A red litmus paper held at the mouth of the test tube turns blue. Which of the following could compound P be? a. zinc sulphate b. copper sulphate c. ferrous sulphate d. ammonium sulphate 7. Glucose reacts with concentrated sulphuric acid to give a very pure form of carbon called sugar charcoal. The reaction taking place is: a. oxidation b. combustion c. dehydration d. combination 8. The basicity of acetic acid is: a. 1 b. 2 c. 3 d. 4 9. A ............... solution is observed after placing Magnesium metal in a solution of Copper sulphate for half an hour. a. Blue b. Colourless c. Reddish brown d. Dirty green 10. An element with atomic no. ............... will form an acidic oxide. a. 3 b. 17 c. 11 d. 13 11. Unsaturated hydrocarbons undergo: a. Addition reaction b. Substitution reaction c. Oxidation reaction d. Redox reaction 12. Copper, Zinc and Tin are the metals alloyed to form: a. Duralumin b. Brass c. Bronze d. Solder 13. Conversion of Ethanol to Ethene by the action of concentrated sulphuric acid involves: a. Dehydration b. Dehydrogenation c. Dehydrohalogenation d. Hydrolysis 14. he oxidizing agent in the equation S + 2H 2SO4 3SO2 + 2H2O is: a. Sulphur b. Sulphuric acid c. Sulphur dioxide d. Water 15. Electron Affinity is maximum in: a. Mg b. Ar c. Li d. Br Question 2: 1. Match the following Column A with Column B. Column A [5] Column B Aluminium Covalent compound Sulphuric acid Carbonate ore Calcination Hall Heroult s process Calcium Chloride Contact Process Carbon tetrachloride Electrovalent compound 2. Complete the following by choosing the correct answers from the bracket: [5] (a) If an element has one electron in the outermost shell then it is likely to have the ................ [smallest/ largest] atomic size amongst all the elements in the same period. (b) ................ [sulphuric acid/ hydrochloric acid] does not form an acid salt. (c) A ................ [reddish brown/ dirty green] coloured precipitate is formed when ammonium hydroxide is added to a solution of ferric chloride. (d) Alkanes undergo ................ [addition/ substitution] reactions. (e) An ................ [alkaline/acidic] solution will turn methyl orange solution pink. 3. The following sketch represents the electroplating of an Iron cup with Nickel metal. Study the diagram and answer the following questions: [5] (a) During electroplating the iron cup is placed at the cathode. Why? (b) Name the ion that must be present in the electrolyte. (c) State one condition that is necessary to ensure that the deposit is smooth, firm and even. (d) Write the reaction taking place at the cathode. (e) What change would you observe at the anode? 4. Identify the following: [5] (a) A bond formed between two atoms by sharing of a pair of electrons, with both electrons being provided by the same atom. (b) A salt formed by the complete neutralization of an acid by a base. (c) A reaction in which the hydrogen of an alkane is replaced by a halogen. (d) The energy required to remove an electron from a neutral gaseous atom. (e) A homogenous mixture of two or more metals or a metal and a non-metal in a definite proportion in their molten state. 5. Draw the structural diagram for the following compounds: 1. 1-propanal 2. 1, 2 dichloro ethane 3. But-2-ene [5] (b) Give the IUPAC name of the following organic compounds: SECTION B (40 Marks) (Attempt any four questions from this Section.) Question 3: 1. Identify the reactant and write the balanced equation for the following: Nitric acid reacts with compound Q to give a salt Ca(NO 3)2, water and carbon dioxide. [2] 2. What property of Sulphuric acid is exhibited in each of the following cases: (a) In the preparation of HCl gas when it reacts with Sodium chloride. (b) When concentrated Sulphuric acid reacts with Copper to produce Sulphur dioxide gas. [2] 3. The electron affinity of an element X is greater than that of element Y. (a) How is the oxidising power of X likely to compare with that of Y? (b) How is the electronegativity of X likely to compare with that of Y? (c) State whether X is likely to be placed to the left or to the right of Y in the periodic table? 4. You are provided with the list of chemicals mentioned below in the box: [3] [3] Sodium hydroxide solution, copper carbonate, zinc, hydrochloric acid, copper, dilute sulphuric acid, chlorine, iron Using suitable chemicals from the list given, write balanced chemical equation for the preparation of the salts mentioned below: (a) copper sulphate (b) sodium zincate (c) ferric chloride Question 4: 1. The following questions relate to the extraction of Aluminium by electrolysis. [2] (a) Name the other aluminum containing compound added to alumina. (b) Give a balanced equation for the reaction that takes place at the cathode. 2. A gas cylinder of capacity 40 dm 3 is filled with gas X the mass of which is 20 g. When the same cylinder is filled with hydrogen gas at the same temperature and pressure the mass of hydrogen is 2 g. Find the relative molecular mass of the gas. [2] 3. Give balanced equations for each of the following: (a) Action of warm water on Aluminium nitride. (b) Oxidation of carbon with conc. Nitric acid. (c) Dehydration of ethanol by conc. Sulphuric acid at a temperature of 170 C. [3] 4. With respect to Haber s process answer the following: (a) Temperature of the reaction (b) Catalyst used (c) Balanced equation for the reaction occurring [3] Question 5: 1. Name the main metal used in making of the alloys given below: [2] (a) Duralumin (b) Stainless steel 2. Differentiate between the following pairs based on the criteria given: [2] (a) Sulphuric acid and Nitric acid (using barium chloride solution) (b) Unsaturated and Saturated hydrocarbons (type of bond present) 3. Calcium carbonate reacts with dilute hydrochloric acid as given below: [3] CaCO3 + 2HCl CaCl2 + H2O + CO2 (a) What is the mass of 5 moles of calcium carbonate? (Relative molecular mass of calcium carbonate is 100) (b) How many moles of HCl will react with 5 moles of calcium carbonate? (c) What is the volume of carbon dioxide liberated at S.T.P. at the same time? 4. Identify the gas evolved in each of the following reactions: [3] (a) Methane undergoes complete combustion. (b) Copper carbonate is heated. (c) MnO2 reacts with concentrated HCl. Question 6: 1. Element 'X' forms an oxide with the formula X 2O3 which is a solid with high melting point. 'X' would most likely be placed in the group of the Periodic Table as: [2] (a) Na (b) Mg (c) Al (d) Si Justify your answer in the above question (1). 2. A student was asked to perform two experiments in the laboratory based on the instructions given: [2] Observe the picture given below and state one observation for each of the Experiments 1 and 2 that you would notice on mixing the given solutions. (a) Experiment 1 (b) Experiment 2 3. Copper sulphate solution is electrolysed using copper electrodes. [3] (a) Which electrode [cathode or anode] is the oxidizing electrode? Why? (b) Write the equation for the reaction occurring at the above electrode. 4. X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information complete the following: [3] (a) ............... is the metallic element. (b) Metal atoms tend to have a maximum of ............... electrons in the outermost shell. (c) ............... is the reducing agent. Question 7: 1. The empirical formula of an organic compound is C 3H4N. Its molecular weight is 108. Find the amount of carbon in one mole of the compound. Show all the steps involved. [3] (Atomic weights: C- 12; H- 1; N- 14) 2. (A)Mahesh prepared a basic solution X that has a pH 7. How will the pH of the solution X change on addition of the following: [4] Hydrochloric acid a solution of a base (b) The atomic number of an element is 15. To which group will this element belong to? 3. 8.2 grams of calcium nitrate is decomposed by heating according to the equation 2Ca(NO3)2 2CaO + 4NO2 + O2 Calculate the following: (a) Volume of nitrogen dioxide obtained at STP [4] (b) Mass of CaO formed [Atomic weights: Ca 40 , N 14, O 16] Question 8: 1. Choose the correct answer from the list given below: [2] zinc blende,C 2H2,calamine, CH, haematitezinc blende,C2H2,calamine, CH, haematite (a) The ore which can be concentrated by magnetic separation. (b) Empirical formula of Ethyne. 2. Give balanced equation for the following reactions: [2] (a) Copper reacts with concentrated Nitric acid. (b) Aluminium nitride is treated with warm water. 3. Match the salts underlined in Column A with the most suitable method of preparation given in Column B. [3] Column A Column B (a) ZnCl2 from Zn 1. Precipitation (b) KNO3 from KOH 2. Direct combination (c) CaCO3 from CaCl2 3. Displacement reaction 4. Neutralization 4. Hydrogen chloride gas is prepared in the laboratory by the action of concentrated sulphuric acid on sodium chloride. (a) Give balanced chemical equation for the above reaction. [3] (b) State the method of collection of the gas formed above. (c) What is the property of sulphuric acid that makes it a suitable reagent for the reaction?
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