sample question papers, Exams of Chemistry

Download sample question papers and more Exams Chemistry in PDF only on Docsity! 71 ICSE Specimen Question Paper CHEMISTRY SCIENCE Paper – 2 (Two hours) Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during the 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 I is compulsory. Attempt any four questions from Section II. The intended marks for questions or parts of questions are given in brackets [ ]. SECTION I (40 Marks) Attempt all questions from this Section Question 1 (a) Choose the most appropriate answer. (i) Which of the following is a common characteristic of a covalent compound? A High melting point. B Conducts electricity when it is in the molten state. C Consists of molecules. D Always soluble in water. (ii) Ammonium hydroxide will produce a reddish brown precipitate when added to a solution of : A CuSO4 B Zn(NO3)2 C FeSO4 D FeCl3 (iii) A salt which in solution gives a bluish white precipitate with NaOH solution and a white precipitate with BaCl2 solution is: A CuSO4 B FeSO4 C Fe2 (SO4)3 D CuCl2 72 ICSE Specimen Question Paper (iv) The gas law which relates the volume of a gas to moles of the gas is: A Avogadro’s Law B Gay-Lussac’s Law C Boyle’s Law D Charle’s Law (v) During the electrolysis of acidified water which of the following takes place: A Oxygen is released at cathode. B Oxygen is released at anode. C Hydrogen is released at anode. D Sulphur dioxide is released at anode. (vi) Duralumin is an alloy of A Al and Cu B Cu and Sn C Al and Ag D Al and Fe (vii) Hydrogen chloride can be obtained by adding concentrated Sulphuric acid to: A NaCl B Na2SO4 C Na2CO3 D NaNO3. (viii) Which of the following reactions gives copper as a product A Passing dry ammonia over heated copper oxide. B Adding dilute hydrochloric acid to copper oxide. C Heating copper oxide. D Passing oxygen over heated copper oxide? (ix) Formation of chloroform from methane and chlorine is an example of: A Addition B Dehydration C Substitution D Elimination. 75 ICSE Specimen Question Paper (ii) How many elements are in the second period? (iii) Name the element which has the highest electron affinity. (iv) Name the element which has the highest electro negativity. (v) Name the element which may be placed on group 1 but is not a metal. [5] (b) Fill in the blanks using the correct options: (i) Metals have ------ ionisation potential. (low/ high) (ii) Group 18 elements have ------ valence electrons (4 / 8) with the exception of ---- ( He / Ne) with -------- electrons (2 / 8) in valence shell. (iii) Group 2 elements are called ----- metals (alkali / alkaline earth). [5] Question 3. (a) Draw different isomers having the following molecular formula: (i) C5H12 (chain) (ii) C4H8 (position). [5] (b) What is denatured alcohol? [1] (c) Give two important uses of ethanol. [2] (d) Write equations for: (i) Preparation of ethanol by hydration of C2H4. (ii) Preparation of acetic acid from ethanol. [2] Question. 4 (a) Name the method by which following compounds can be prepared: Select the appropriate method from the following list Neutralization; direct combination; precipitation; metal + acid – use a method only once. (i) Sodium sulphate (ii) Silver chloride (iii) Iron sulphide. [3] (b) How will you distinguish between following pairs of compounds using NH4OH. (i) Copper sulphate and iron(II) sulphate. 76 ICSE Specimen Question Paper (ii) Zinc nitrate and lead nitrate. (iii) Iron(II) sulphate and iron(III) sulphate. [3] (c) Name: (i) A greenish yellow gas with pungent smell. (ii) An oxide which is yellow when hot and white when cold. (iii) A chemical used to deplete ozone layer. (iv) A crystalline salt without water of crystallization. [4] Question. 5 (a) Name one: (i) metal liquid at room temperature. (ii) non-metal which is a conductor of electricity. (iii) neutral oxide. (iv) metallic oxide which cannot be reduced by hydrogen. (v) non-metal which has lustre. [5] (b) (i) Name the chief ore of aluminium. (ii) Name the process used to concentrate the above mentioned ore. (iii) Why is alumina added to cryolite in the electrolytic reduction of aluminium? (iv) Give cathode and anode reactions involved in extraction of aluminium from its above mentioned ore. (v) Name the process used for the concentration of zinc blende. [5] Question 6. (a) Draw a neat and well labelled diagram for the silver plating on an iron spoon. [3] (b) Copy and complete the following table related to electrolysis. S.No. Name of Electrolyte Name of Cathode Name of Anode Product at Cathode Product at Anode 1. CuSO4 (aq.) Copper Copper 2. PbBr2 (molten) Platinum Platinum [4] 77 ICSE Specimen Question Paper (c) Classify the following as oxidation and reduction reaction, also complete the reaction. (i) Cu Cu2+ (ii) Fe3+ Fe2+ (iii) Cl- Cl [3] Question. 7 (a) A compound has the following percentage composition by mass: Carbon – 54.55%, Hydrogen – 9.09% and Oxygen – 36.26%. Its vapour density is 44. Find the Empirical and Molecular formula of the compound. (H = 1; C = 12; O = 16) [5] (b) Give the electron dot structure of the following: (i) NH3 (ii) CH4 (iii) H3O+ [3] (c) Compare the properties of covalent and electrovalent compounds on the following points: (i) Solubility (ii) Structure. [2]