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Guess Paper – 2013
Class – X
Subject – CHEMISTRY
SCIENCE Paper – 2
(Time – One hour and a half)
(Full Maks – 80)
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) Compound X consists of molecules. In the liquid state, X will :
A. become ionic
B. be an electrolyte
C. conduct electricity
D. not conduct electricity.
(ii) The reagent used to distinguish zinc nitrate solution from magnesium nitrate
solution is :
A. ammonium hydroxide
B. sodium hydroxide
C. potassium hydroxide
D. nitric acid.
(iii) A chloride of metal soluble in excess of ammonium hydroxide is :
A. sodium chloride
B. potassium chloride
C. zinc chloride
D. calcium chloride.
(iv) The colour of ferrous salt is :
A. light blue
B. light green
C. yellow
D. white.
(v) We can not store copper sulphate solution in a :
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A. copper vessel
B. aluminium vessel
C. iron vessel
D. zinc vessel.
(vi) A salt which is a weak electrolyte :
A. sodium hydroxide
B. potassium chloride
C. sodium bicarbonate
D. zinc chloride.
(vii) A metal which occurs free in nature :
A. zinc
B. gold
C. silver
D. magnesium.
(viii) An alloy of steel in daily use is :
A. duralumin
B. bronze
C. invar
D. stainless steel.
(ix) The vapour density of the fifth member of the homologous series of alkane is :
A. 22
B. 29
C. 36
D. 42.
(x) The electron affinity of the elements in group 1 to 7 :
A. increases
B. decreases
C. increases and the decreases
D. decreases and then increases.
[10]
(b) The equation for the action of heat on sodium bicarbonate is :
2NaHCO3 → Na2CO3 + H2O + CO2
(i) How many moles of H2O is produced when 1 mole of NaHCO3 decomposes.
(ii) What volume of CO2 is produced when 1 mole of NaHCO3 is decomposed.
(iii) Find the mass of Na2CO3 formed when 1 mole of NaHCO3 is heated.
(iv) Find the mass of NaHCO3 required to produce 5 moles of CO2.
(v) Find the mass of NaHCO3 required to produce 2 moles of H2O.
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(c) Give one example each of the following :
(d)
(e)
(f)
(g)
1. Cracking
2. Hydrogenation
3. Dehydration
4. Substitution reaction
5. Addition reaction.
[5]
State one observation each for the following :
(i) Manganese dioxide is heated with concentrated HCl.
(ii) Silver nitrate solution is added to dilute hydrochloric acid.
(iii) Concentrated sulphuric acid is added to sugar crystals.
(iv) Ethylene is passed through dilute bromine water.
(v) Copper sulphate solution is electrolysed using copper electrodes.
[5]
Write balanced chemical equation for the following :
(i) Solution of bromine in carbon tetrachloride is treated with acetylene.
(ii) Iron pyrite is roasted.
(iii) Copper chips are treated with concentrated sulphuric acid.
(iv) Silver nitrate is heated.
(v) Sulphur dioxide is passed through chlorine water.
[5]
Name the following (Formula not accepted) :
(i) A double salt used for the sedimentation of muddy water.
(ii) A nitrate which does not leave behind any solid residue on heating.
(iii) A gas which forms red precipitate with Fehling’s solution.
(iv) A black metallic oxide which dissolves in nitric acid to give greenish blue solution .
(v) A solution which reacts with soluble salt of Lead to form a yellow precipitate. [5]
Draw the relevant structural formula of :
(i) marsh gas
(ii) ethane
(iii) acetylene
(iv) propylene
(v) 1 – butyne.
[5]
SECTION – II (40 Marks)
Attempt any four questions from this section.
Question 2.
(a) With reference to the periodic table answer the following :
(i) Name the smallest atom in name third period.
(ii) The most non-metallic element in the second period.
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(iii) The noble gas having duplet arrangement of electrons.
(iv) An alkali earth metal in the third period. (v) The alkali metal in the second period. [5]
(b) Differentiate between the following terms :
(i) Ionisation energy and electron affinity.
(ii) Electronegativity and electron affinity.
[5]
Question 3.
(a) Give three uses each of ethylene and acetylene.
[2]
(b) Giving equation, write under what conditions do ethane get converted to
(i) ethyl alcohol
(ii) acetaldehyde
(iii) acetic acid.
[3]
(c) What happens when (give balanced equations) :
(i) Ethylene is burnt in an excess of oxygen.
(ii) Ethylene reacts with chlorine.
(iii) Ethylene combines with hydrogen chloride.
(iv) A mixture of ethylene and hydrogen is passed over nickel at 159˚ C.
(v) Ethylene is heated at 400˚ C under very high pressure in presence of traces of O2. [5]
Question 4.
(a) The fountain experiment can be carried out with both hydrogen chloride and ammonia.
(i) What is the common property of hydrogen chloride and ammonia demonstrated
by the fountain experiment ?
(ii) Litmus solution is added to :
1. Hydrogen chloride solution and
2. Ammonia solution.
3. What is seen in each case ?
[3]
(b) (i) Magnesium is burnt in air and water is added to the product. The smell of ammonia is
detected. Write the equation for the reaction which produces ammonia in this situation.
(ii) Choose the correct words to complete the following sentence :
Ammonia is -------------- (more/less) dense than air, therefore, it is collected by
------------ (upward/downward) delivery.
[3]
(c) Ammonia reacts with oxygen in two different ways depending on the presence or absence
of a catalyst.
(i)
1. Write the equation for the reaction between ammonia and oxygen in the presence
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of a catalyst.
2. Name the catalyst. 3. What is the importance of this reaction ?
(ii) Write the equation for the reaction between ammonia and oxygen when no
catalyst is used.
[4]
Question 5.
(a) Name the following :
(i) A metal other than zinc which displaces copper from copper (II) sulphate solution.
(ii) A metal other than manganese present in duralumin but not in mangalium.
(iii) The form of iron which has 0.1 to 0.5 % carbon impurity and is used in making
nuts and bolts.
(iv) the metal rendered passive or unreactive by concentrated or fuming nitric acid.
(v) A metal other than mercury in a liquid amalgam.
[5]
(b) Answer the following :
(i) write balanced equation for Al powder when warmed with hot and
concentrated caustic soda solution.
(ii) Name the ore of zinc containing its sulphide.
(iii) In the process of extracting zinc, the above name ore is roasted. Write the
equation for the reaction which takes place when the sulphide ore is roasted.
(iv) Name the substance used to reduce the roated ore. Write the equation for
the reaction.
(v) Iron is removed from a blast furnace as a liquid, state how zinc leaves a furnace. [5]
Question 6.
(a) Give the product of electrolysis in each case giving ionic equations :
(i) Molten lead bromide using graphite electrodes.
(ii) Acidified water using platinum electrodes.
(iii) CuSO4 solution using platinum electrodes.
(iv) Dilute NaCl solution using platinum or graphite electrodes.
(v) Concentrated NaCl solution using platinum electrodes.
[5]
(b) Explain the following :
(i) A solution of cane sugar does not conduct electricity but a solution of sodium
chloride is a good conductor.
(ii) During the electrolysis of an aqueous solution of NaCl, H+ ions are reduced
at cathode and not Na+ ions.
(iii) Copper is a good conductor of electricity but it is non-electrolyte.
[3]
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(c) Copy and complete the following table which refers to two practical applications of
electrolysis.
[2]
Process
Silver plating
spoon
Purification of
copper
Anode
Electrolyte
Cathode
Question 7.
(a) What volume of oxygen would be required to burn completely 400 mL of acetylene (C2H2) ?
Also calculate the volume of carbon dioxide formed.
2C2H2 + 5 O2 → 4CO2 + 2H2O (l)
[4]
(b) Calculate the percentage of Sodium [Na] in Na2B4O7.10H2O,
[H = 1, B = 11, O = 16, N = 23]
[2]
(c) A hydrocarbon contains 10.5 g of carbon per gram of hydrogen. Calculate the empirical
formula.
[4]
Paper Submitted By:
Name M. P. Keshari
Email
mpkeshari@yahoo.com
Phone No.
09434150289
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