1ST PRE BOARD EXAMINATION 2021-22
SUBJECT – Chemistry
(Science Paper-2)
CLASS – X
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Maximum Marks: 40
Time allowed: One and a half hours
Answers to this paper must be written on paper provided separately.
You will not be allowed to write during the first 10 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.
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Attempt all questions from Section A and any three questions from section B.
The intended marks for questions or part of the questions are given in the brackets. [ ]
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Section – A
(Attempt all questions)
Question (1)
Choose the correct answer to the questions from the given option. (Do not copy the question, write the correct answer only) [10]
(i) The main ore used for the extraction of iron is:
(a) Haematite (b) Calamine
(c) Bauxite (d) Cryolite
(ii) Ammonia is dried by passing it through:
(a) Quick lime (b) Concentrated H2SO4
(c) Calcium Chloride (d) Hydrogen Chloride
(iii) Which one of the following will not produce an acid when made to react with water.
(a) Carbon Monoxide (b) Carbondioxide
(c) Nitrogen dioxide (d) Sulphur trioxide
(iv) Hydrogen chloride gas being highly soluble in water is dried by:
(a) Anhydrous calcium chloride (b) Phosphorous pentaoxide
(c) Quick line (d) Concentred
(v) Fused alumina is reduced to aluminium by electrolylic reduction, since
(a) Alumina is highly stable (b) Alumina is least stable
(c) Alumina is not reduced by drying agents (d) Alumina is not reduced by reducing agents
(vi) The aim of the fountain experiment is to prove that:
(a) HCI turns blue litmus red (b) HCI is denser than air
(c) HCI is highly soluble in water (d) HCI fumes in moist air
(vii) Nitrogen gas can be detained by heating.
(a) Ammonium nitrate (b) Ammonium nitrite
(c) Magnesium nitride (d) Ammonium chloride
(viii) When magnesium directly combine with Nitrogen it produces:
(a) M3N2 (b) Mg3N2
(c) Mn3N2 (d) Mg2N3
(ix) The number of C-H bounds in ethane molecular are.
(a) Four (b) Six
(c) Eight (d) Ten
(x) The IUPAC name of acetylene is
(a) propane (b) propyne
(c) ethane (d) ethyne
Section – B
(Attempt any three questions from this section)
Question (2)
(i) Give reasons for the following: [2]
(a) Aluminum is used in light fixtures.
(b) Aluminum is used in transmission wires.
(ii) Write equations for the following: [2]
(a) Dilute hydrochloric acid and sodium thiosulphate.
(b) Dilute hydrochloric acid and lead nitrate.
(iii) Draw the structural diagram of: [3]
(a) Ethane
(b) But-1-ene
(c) 1,3-dibromobutane
(iv) Give a balanced chemical equation for each of the following: [3]
(a) Action of nitric acid on Sulphur.
(b) Laboratory preparation of Nitric acid.
(c) Reaction of Ammonia with Nitric acid.
Question (3)
(i) Explain: [2]
(a) Chain isomerism
(b) Position isomerism
(ii) Complete and balance the following equations: [2]
(a) Na + O2 _________
(b) Al + _________ Al2O3
(iii) Fill in the blanks with the correct words from the brackets: [3]
Alkenes active
(a) _________(saturated/unsaturated) hydrocarbon.
(b) They differ from alkanes due to the presence of _________(double/single) bonds.
(c) Alkenes mainly undergo _________(addition/substitution) reaction.
(iv) Name the following: [3]
(a) Gas released during roasting of sulphide ores.
(b) A substance used to remove excess of chlorine.
(c) A gas which turns lead acetate paper black.
Question 4
(i) Name the following: [2]
(a) Name agent used to dry HCl gas.
(b) Mixture of one part of HNO3 and three parts of HCl.
(ii) Name the gas evolved in each case: [2]
(a) The gas produced by the action of dilute nitric acid on copper.
(b) The gas produced on heating sodium nitrate.
(iii) Give chemical equations for the following: [3]
(a) Reaction of Ammonia with excess of chlorine.
(b) Reaction of Ammonia with carbon dioxide.
(c) Catalytic oxidation of ammonia.
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Question (5)
(i) Write IUPAC names of the following organic compounds as given below: [2]
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(ii) Choose the correct answer: [2]
(a) The organic compound which undergoes substitution reaction is–
(C2 H2 or C2 H4 or C10 H18 or C2H6)
(b) The IUPAC name of dimethyl ether is–
(Ethoxy methane or Methoxy methane or methoxy ethane or Ethoxy ethane)
(iii) Name the alloys form from the following composition: [3]
(a) Copper and zinc
(b) Copper, zinc and tin
(c) Magnesium & Aluminium
(iv) Answer the following related to laboratory preparation of ammonia [3]
(a) What is catalytic promoter used in reaction?
(b) What should be optimum temperature for high yield of ammonia?
(c) Write catalyst used for above preparation.
Question (6)
(i) Distinguish between the following: [2]
(a) Dilute HCl and ammonia
(b) Solution of H2SO4 and NH4OH
(ii) Give an equation of the reaction in each case: [2]
(a) Hydrogen sulphide gas is passed through concentrated sulphuric acid.
(b) Concentrated sulphuric acid react with formic acid.
(iii) Write any three uses of nitric acid. [3]
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