ICSE Class 10 For Chemistry Question Paper Solved Set E

Students should refer to ICSE Class 10 Chemistry Question Paper solved Set E given below which will help them to prepare for the upcoming ICSE Chemistry exams. Students should read ICSE Chemistry Class 10 Books to make sure they are completely prepared and should also refer to ICSE Class 10 Chemistry Solutions to understand all questions and their answers.

ICSE Class 10 Chemistry Question Paper solved Set E

PAPER 2 (CHEMISTRY)
(One hour and A half)
Answer 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 [ ].

ICSE Class 10 Chemistry Question Paper solved Set E
Section I (40 Marks)
Attempt all questions from this Section.

Question 1 (a) From the list given below, select the word (s) required to correctly complete blanks (i) to (v) in the following passage. The words from the list are to be used only once. Write the answers as (a) (i), (ii), (iii) and so on. Do not copy the passage.

Ans. (ammonia, ammonium, carbonate, carbon dioxide, hydrogen, hydronium, hydroxide, precipitate, salt, water) :

(a) A solultion M tuns blue litmus red, so it must contain (i) ………… ions ; another solution O turns red litmus blue and hence, must contain (ii) ……ions.
(b) When solution M and O are mixed together, the products will be (iii) ………… and (iv) …………
(c) If a piece of magnesium was put into a solution M, (v) ………… gas would be evolved.(5)

Ans. (a) (i) hydronium, (ii) hydroxide
(b) (iii) salt, (iv) water
(c) (v) hydrogen

(b) Identify the gas evolved in the following reactions when :
(i) sodium propionate is heated with soda lime.
(ii) potassium sulphite is treated with dilute hydrochloric acid.
(iii) sulphur is treated with concentrated nitric acid.
(iv) a few crystals of KNO3 are heated in a hard glass test tube.
(v) concentrated hydrochloric acid is made to react with manganese dioxide. (5)

Ans. (i) Ethane gas
(ii) Sulphur dioxide gas
(iii) Nitrogen dioxide gas
(iv) Oxygen gas
(v) Chlorine gas

(c) State one appropriate observation for each of the following:
(i) Concentrated sulphuric acid is added drop wise to a crystal of hydrated copper sulphate.
(ii) Copper sulphide is treated with dilute hydrochloric acid.
(iii) Excess of chlorine gas is reacted with ammonia gas.
(iv) A few drops of dilute hydrochloric acid are added to silver nitrate solution, followed by addition of ammonium hydroxide solution.
(v) Electricity is passed through molten lead bromide.

Ans. (i) The blue coloured hydrated copper sulphate crystals disintegrate with a hissing sound, giving off steam and leaving behind white residue.
(ii) A colourless gas with a smell of rotten eggs is given off and a green coloured solution is formed.
(iii) When chlorine gas is in excess as compared to ammonia gas, the ammonia reduces chlorine to hydrochloric acid.
(iv) A curdy white precipitate is formed. This precipitate dissolves in excess of ammonium hydroxide to form a colourless solution.
(v) The molten lead bromide breaks into lead metal which discharges at cathode and bromine gas which discharged at anode.

(d) Give suitable chemical terms for the following :
(i) A bond formed by a shared pair of electrons with both electrons coming from the same atom.
(ii) A salt formed by incomplete neutralisation of an acid by a base.
(iii) A reaction in which hydrogen of an alkane is replaced by a halogen.
(iv) A definite number of water molecules bound to some salts.
(v) The process in which a substance absorbs moisture from the atmosphere air to become moist, and ultimately dissolves in the absorbed water.

Ans. (i) Coordinate bond
(ii) Acidic salt
(iii) Subsitution reaction
(iv) Water of crystallisation
(v) Deliquescence

(e) Give a chemical test to distinguish between the following pairs of compounds :
(i) Sodium chloride solution and sodium nitrate solution.

Ans. Add silver nitrate solution to sodium chloride solution and sodium nitrate solution. In case of sodium chloride, a curdy white precipitate is formed. In case of sodium nitrate solution the reaction mixture remains colourless.

(ii) Hydrogen chloride gas and hydrogen sulphide gas.
Ans. Moist lead acetate paper turns black in case of hydrogen sulphide gas, but does not change its colour in case of hydrogen chloride gas.

(iii) Ethene gas and ethane gas.
Ans. To the given gas add few drops of bromine solution in carbon, tetra-chloride. In case of ethene gas, the reddish colour of bromine discharges. However, in case of ethane gas the reddish colour of bromine does not discharge.

(iv) Calcium nitrate solution and zinc nitrate solution.
Ans. To each of the solution add first ammonium hydroxide solution in small amount and then in excess. In case of calcium nitrate a fine white precipitate is formed, which does not dissolve in excess of sodium hydroxide. In case of zinc nitrate a gelatin like white precipitate is formed which dissolves in excess of sodium hydroxide.

(v) Carbon dioxide gas and sulphur dioxide gas.
Ans. To each of the gas add few drops of acidified potassium dichromate solution. In case of carbon dioxide no change takes place. In case of sulphur dioxide, potassium dichromate solution turns blue.

(f) Choose the most appropriate answer from the following options :
(i) Among the period 2 elements, the element which has high electron affinity is
(a) Lithium
(b) Carbon
(c) Chlorine
(d) Fluorine
Ans. (d) Fluorine has highest electron affinity

(ii) Among the following compounds identify the compound that has all three bonds (ionic, covalent and coordinate bond).
(a) Ammonia
(b) Ammonium chloride
(c)Sodium hydroxide
(d) Calcium chloride
Ans. (b) Ammonium chloride has all the three electronic bonds

(iii) Identify the statement that is incorrect about alkanes :
(a) They are hydrocarbons.
(b) There is single covalent bond between carbon and hydrogen
(c) They can undergo both substitution as well as addition reactions
(d) On complete combustion they produce carbon dioxide and water.
Ans. (c) They can undergo both substitution as well as addition reactions.

(iv) Which of these will act as non-electrolyte ?
(a) Liquid carbon tetrachloride
(b) Acetic acid
(c) Sodium hydroxide aqueous solution acid.
(d) Potassium chloride aqu. solution.
Ans. (a) Liquid carbon tetrachloride is non-electrolyte

(v) Which one of the following will not produce an acid when made to react with water ?
(a) Carbon monoxide
(b) Carbon dioxide
(c)Nitrogen dioxide
(d) Sulphuric trioxide.
Ans. (a) Carbon monoxide gas

(vi) Identify the metallic oxide which is amphoteric in nature :
(a) Calcium oxide
(b) Barium oxide
(c) Zinc oxide
(d) Copper (II) oxide
Ans. (c) Zinc oxide is an amphoteric oxide

(vii) In the given equation identify the role played by concentrated sulphuric acid S + 2H₂SO₄ ¾¾ → 3SO₂ + 2H₂O :
(a) Non-volatile acid
(b) Oxidising agent
(c)Dehydrating agent
(d) none of these
Ans. (b) Concentrated sulphuric acid acts as oxidising agent

(viii) Nitrogen gas can be obtained by heating :
(a)Ammonium nitrate
(b) Ammonium nitrite
(c) Magnesium nitric
(d) Ammonium chloride
Ans. (b) Ammonium nitrite

(ix) Which of the following is not a typical property of an ionic compound ?
(a) High melting point
(b) Conducts electricity in the molten and in the aqueous solution state
(c) They are insoluble in water
(d) They exist as oppositely charged ions even in the solid state.
Ans. (c) Ionic compounds are generally insoluble in water

(x) The metals zinc and tin are present in the alloy :
(a) Solder
(b) Brass
(c) Bronze
(d) Duralumin. (10)
Ans. Bronze (c)

(g) Solve the following :
(i) What volume of oxygen is required to burn completely 90 dm³ of butane under similar conditions of temperature and pressure ?
2C₄H₁₀ + 13O₂ ¾¾ → 8CO₂ + 10H₂O

Ans.

(ii) The vapour density of a gas is 8. What would be the volume occupied by 24.0 g of the gas at STP ?

Ans. V.D. of gas = 8
∴ Molecular mass of gas = 2 × V.D. = 2 × 8 = 16
∴ Gram molecular mass of gas = 16 g
16 g of gas at STP occupies = 22.4 dm³

∴ 24 g of gas at STP occupies = 22.4 x24 /16 = 33.6 dm3.

(iii) A vessel contains X number of molecules of hydrogen gas at a certain temperature and pressure. How many molecules of nitrogen gas would be present in the same vessel under the same conditions of temperature and pressure ? (1)
Ans. According to Avogadro’s law, equal volumes of all gases under similar conditions of temperature and pressure contain equal number of molecules.
Number of molecules of nitrogen = X.

ICSE Class 10 Chemistry Question Paper solved Set E
SECTION II (40 Marks)
Attempt any four questions from this Section

Question 2

• • In this table H does not represent hydrogen.
• • Some elements are given in their own symbol and position in the periodic table.
• • While others are shown with a letter.
  With reference to the table answer the following questions.
  (i) Identify the most electronegative element. (1)
  (ii) Identify the most reactive element of group 1. (1)
  (iii) Identify the element from period 3 with least atomic size. (1)
  (iv) How many valence electrons are present in Q ? (1)
  (v) Which element from group 2 would have the least ionization energy ? (1)
  (vi) Identify the noble gas of the fourth period. (1)
  (vii) In the compound between A and H what type of bond would be formed and give the molecular formula for the same. (2)
  Ans. (i) J
  (ii) R
  (iii) M
  (iv) 5
  (v) T
  (vi) Y
  (vii) A and H form an electrovalent compound and its formula is A₂H.
  
  (b) Compare the compounds carbon tetrachloride and sodium chloride with regard to solubility in water and electrical conductivity. (2)
  Ans. Carbon tetrachloride is insoluble in water and is not conducting in nature.

Sodium chloride is soluble in water and is conducting in nature in aqueous state or molten state.

Question 3
(a) Choosing the substances from the list given below, write balanced chemical equations for the reactions which would be used in the laboratory to obtain the following salts :

(i) Sodium sulphate (ii) Zinc carbonate
(iii) Copper (II) sulphate (iv) Iron (II) sulphate. (4)

(b) State two relevant observations for each of the following :
(i) Ammonium hydroxide solution is added to copper (II) nitrate solution in small quantities and then in excess.
(ii) Ammonium hydroxide solution is added to zinc nitrate solution in minimum quantities and then in excess.
(iii) Lead nitrate crystals are heated in a hard glass test tube.

Ans. (a) (i) Sodium carbonate and dilute sulphuric acid.
Na₂CO₃ + H₂SO₄(dil) → Na₂SO₄ + CO₂ + H₂O
(ii) Zinc nitrate and sodium carbonate.
Zn(NO₃)2(aq) + Na₂CO₃(aq) → ZnCO₃(s) + 2NaNO₃(aq)
(iii) Copper carbonate and dilute sulphuric acid.
CuCO₃(s) + H₂SO₄(aq) → CuSO₄(aq) + H₂O(l) + CO₂(g)
(iv) Iron and dilute sulphuric acid.
Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂(g)

(b) (i) With small amount of ammonium hydroxide, a bluish white precipitate is formed. This precipitate dissolves in excess of ammonium hydroxide to form a deep blue solution.
(ii) A white gelatin like precipitate is formed which dissolves in excess of ammonium hydroxide.
(iii) It gives off a reddish brown gas (NO2). The crystals crumble to form a powdery mass, which is yellow when hot and white when cold.

Question 4
(a) Copper sulphate solution is electrolysed using copper electrodes.
Study the diagram given below and answer the question that follows:

(i) Which electrode to your left or right is known as the oxidising electrode and why? (2)
Ans. Left (anode ; + ve terminal of the battery). It is called the
oxidising electrode as anions give their electrons to anode,
and thus undergo oxidation.
(ii) Write the equation representing the reaction that occurs. (1)
Ans. At cathode (–ve terminal of battery ; rich in e–)
Cu²⁺ + 2e^– → Cu
At anode (+ ve terminal of battery ; deficient in e–)
Cu – 2e^– → Cu²⁺
(iii) State two appropriate observations for the above electrolysis reaction. (2)
Ans. The size of anode gradually decreases and that of cathode gradually increases. However, there is no change in the colour of copper sulphate solution.

Using the information above, complete the following :
(i) …………. is the metallic element.
(ii) Metal atoms tend to have a maximum of …………. electrons in the outermost energy level.
(iii) Non-metallic elements tend to form …………. oxides while metals tend to form …………. oxides.
(iv) Non-metallic elements tend to be …………. conductors of heat and electricity.
(v) Metals tend to …………. electrons and act as …………. agents in their reactions with elements and compounds. (5)
Ans. (i) Y, (ii) Three (iii) acidic, basic (iv) bad (v) lose, reducing

Question 5
a. Give balanced equations for each of the following :
(i) Reduction of hot Copper (II) oxide to copper using ammonia gas.
Ans. (i) 3CuO + 2NH₃ → 3Cu + 3H₂O + N₂ (4)
(ii) Oxidation of carbon with concentrated nitric acid.
Ans. C + 4HNO₃ → 2H₂O + 4NO₂ + CO₂
(iii) Dehydration of concentrated sulphuric acid with sugar crystals
Ans. C₁₂H₂₂O₁₁ + 11H₂SO₄ → 12C + 11H₂O

(b) Copy and complete the following table relating to important industrial process :

Ans.

(c) The following questions relate to the extraction of aluminium by electrolysis :

(i) Name the other aluminium containing compound added to alumina and state its significance.
Ans. The compound is cryolite [Na₃AlF₆]
The addition of cryolite lowers the melting point of alumina from 2050^oC to 950^oC.
Furthermore, it increases the electrical conductivity of the molten alumina.

(ii) Give the equation for the reaction that takes place at the cathode.
Ans. Al3+ + 3e– ® Al

(iii) Explain why is it necessary to renew the anode periodically.
Ans. The anode (which is made of carbon) is attacked by nascent oxygen formed due to the discharge of O₂– ions and changes to carbon dioxide. As the anode is gradually consumed, it is periodically renewed.

Question 6
(a) Give balanced equations for the laboratory preparations of the following organic compounds : (4)
(i) A saturated hydrocarbon from iodomethane.

(c) Give reasons for the following :
(i) Methane does not undergo addition reactions, but ethene does.
Ans. All the four covalent bonds between the carbon and hydrogen are fully shared. Thus the hydrogen atom can only be substituted by more reactive atoms or group of atoms. There is no scope of addition of reactive atoms in its molecule.
However, in case of ethene there is a double bond between the two carbon atoms. These bonds are under strain and hence can be easily broken by more reactive atoms to form other compounds which are saturated in nature.

(ii) Ethyne is more reactive than ethane.
Ans. Ethyne has a triple covalent bond (—C º C —) between two carbon atoms, whereas ethane has a single covalent bond (—C = C —) between the two carbon atoms. So, the strain in the bonding of ethyne is far more than ethane. This accounts of the reactivity of ethyne as its bonds break more easily than that of ethane.

(iii) Hydrocarbons are excellent fuels. (3)
Ans. All the constituents of hydrocarbon (carbon and hydrogen) are highly combustible and do not have any uncombustible content. So, hydrocarbons are excellent fuels.

Question 7

(i) Calculate the mass of KClO3 required to produce 6.72 litre of O2 at STP. atomic masses of K = 39, Cl = 35.5, O =16
Ans. 67.2 lt of oxygen at STP is librated from potassium chlorate = 245 g
∴ 6.72 lt of oxygen at STP is liberated from potassium chlorate = 245 x 6.72 / 67.2 = 24.5 g

(ii) Calculate the number of moles of oxygen present in the above volume and also the number of molecules. (2)
Ans. 22.4 lt of oxygen and STP = 1 mole.
∴ 6.72 lt of oxygen at STP = 6.72 / 22.4 = 0.3 moles
1 mole of oxygen contains number of molecules = 6 × 10²³
∴ 0.3 mole of oxygen contain number of molecules = 6 x 10²³ x 0.3 /1 = 1.8 × 10²³ molecules

(iii) Calculate the volume occupied by 0.01 mole of CO2 at STP. (1)
Ans. 1 mole of carbon dioxide gas at STP occupies = 22.4 lt
∴ 0.01 mole of carbon dioxide gas at STP occupies = 22.4 x 0.01/1 = 0.224 lt = 224 cm³

(b) Identify the following substances which are underlined :
(i) An alkaline gas which produces dense white fumes when reacted with hydrogen chloride gas. Ans. Ammonia gas.
(ii) An acid which is present in vinegar. Ans. Acetic acid or ethanoic acid.
(iii) A gas which does not conduct electricity in the liquid state but conducts electricity when dissolved in water. Ans. Hydrogen chloride gas.
(iv) A dilute mineral acid which forms a white precipitate when treated with barium chloride solution. Ans. Dilute sulphuric acid.
(v) The element which has the highest ionization potential.
Ans. Fluorine.