Formatting page ...
ICSE Chemistry: Model Paper 3 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). Fill in the blanks with appropriate word/s in each case : (i) Increase in nuclear charge of an atom ________ [decreases/increases] the tendency of the atom to lose electrons. (ii)Electrons with low electronegativity are usually _________ [metallic/non-metallic]. (iii) An atom is said to be a non-metal if it _________ [gains/loses] one or more electrons. (iv)Covalent compounds are formed by sharing electron pairs between non-metallic atoms. Non-metallic atoms having ___, ___, ____ Valence electrons [4, 5, 6, 7] share one, two or three pairs of electrons respectively. (v) The covalent molecule containing three single covalent bonds is ________ [water / methane / ammonia] (b) Give reason/s for the following : (i) NH3 gas a covalent compound dose not conduct electricity but its aq.soln. NH4OH is a weak electrolyte. (ii) Concentrated sulphuric acid is a weaker acid compared to dilute sulphuric acid. (iii) Zinc chloride is stored in air tight bottles. (iv) Sulphuric acid forms two types of salts on reaction with an alkali. (v)The metals - copper, silver and lead are electrorefined but K, Na and Ca are not. (c)Complete the following :(i) Salts of _______ [normal/transition] elements are generally coloured. (ii) The hydroxide which is soluble in excess of NaOH is ______ [Zn(OH)2 / Fe(OH)3 / Fe(OH)2] (iii) The salt which will not react with NH4OH solution _______ [ZnCl2/CuCl2/NH4Cl /FeCl2] (iv) The electrode at which anions donate excess electrons and are oxidized to neutral atoms is the _____ [anode/cathode] (v) Salts ionize in aq.soln. on passage of electric current to give ______ [negative / positive] ions other than H+ ions. (d) Define the following :(i) Molecular weight, (ii) Molecular formula, (iii) Empirical formula, (iv) Aqua Regia and (v) Electrolysis. Jaydip.Chaudhuri@saralabirlaAcademy 1
|
