ICSE Chemistry SOLVED Specimen Paper 2027 PDF

Specimen Paper for  ICSE Chemistry 2027 Solved PDF

If you are searching for the ICSE Chemistry specimen paper 2027 solutions, the council's draft marking scheme gives only short hints. Students often lose marks because they copy those hints as they are. Here, each answer is written the way an examiner expects it: the correct equation, the right chemical name, a clear observation or a short reason, with the marks shown against each part.

The ICSE Class 10 Chemistry Specimen Paper 2027 (code T27 522) is an 80-mark, 2-hour paper from CISCE. Below, every question is solved with the exact equations, observations and calculations an examiner looks for. The answers follow the council’s marking scheme and Dr. Viraf J. Dalal’s Simplified ICSE Chemistry. In Chemistry, marks go to balanced equations, correct conditions, named products and neat dot-and-cross diagrams, so each answer is written with those in mind. Attempt the paper yourself first, then check your answers question by question.

On this page you get every question of the specimen paper, solved in full, with answers written the way the council expects them: short, precise, and aligned with the hints in the official draft marking scheme. Wherever the council has given only a keyword or a hint, we have expanded it into a complete, exam-ready answer using the language of the prescribed textbook, Dr. Viraf J. Dalal’s Simplified ICSE Chemistry, so that you know exactly how much to write for the marks given.

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Specimen Paper for Class 10 ICSE Chemistry 2027 Solved

ICSE Class 10 Chemistry Solved Specimen Paper 2027

Question 1.

Section - A

(i) (c) X - iodine, Y - bromine. Reactivity of halogens decreases down the group (F > Cl > Br > I), so iodine is less reactive than bromine. In the other options, X is the more reactive element.

(ii) (d) concentrated sulphuric acid followed by water. SO3 is first absorbed in conc. H2SO4 to form oleum (H2S2O7), which is then diluted with water. Adding water directly to SO3 forms a harmful acid mist.

(iii) In acidic solutions, current is carried by ions. Electrolytes (solutions and melts) conduct through mobile ions; metals conduct through free electrons.

(iv) 3 and 4. A pH below 7 and the reaction of the acid with a basic oxide (CuO) to give a salt and water show acidic nature. Statement 1 is the test for sulphate ions; statement 2 shows the oxidizing property of the concentrated acid.

(v) (d) P - zinc, Q - copper (II) oxide. Zn + 2HCl gives ZnCl2 + H2. Hydrogen reduces hot CuO: CuO + H2 gives Cu + H2O. Copper does not react with dilute HCl, and hydrogen cannot reduce the oxides of Mg or Ca.

(vi) (a) acid. They form hydrogen halides, HCl and HI, which give acids in water.

(vii) (a) Both the statements are true. Halogens readily gain one electron to complete the octet.

(viii) (c) Both (A) and (R) are true, and (R) is the correct explanation of (A). A lot of energy is needed to overcome the strong forces between ions in the crystal.

(ix) (b) Q. Green pH paper means pH 7 (neutral). Red shows an acid, blue and violet show alkalis.

(x) (a) Only 1. Propanol is C3H7OH = C3H8O. Propanal is C3H6O and propanoic acid is C3H6O2.

(xi) (b) C2H4. Molecular mass = 2 x vapour density = 2 x 14 = 28. C2H4 = (2 x 12) + (4 x 1) = 28.

(xii) (b) H3O+. Oxygen in the hydronium ion has one lone pair left after forming three bonds (one is a coordinate bond). OH- has three lone pairs; NH4+ and H+ have none.

(xiii) (b) Sodium sulphide. Na2S + 2HCl gives 2NaCl + H2S. Hydrogen sulphide turns lead acetate paper black (PbS) and decolourises acidified KMnO4. Sulphur dioxide from sodium sulphite does not blacken lead acetate paper.

(xiv) (c) 3 and 4. Burning ethanol gives CO2 and H2O. MgCO3 + H2SO4 gives MgSO4 + H2O + CO2. Reaction 1 gives hydrogen, and reaction 2 gives CaO and CO2.

(xv) (d) 4.48 litres. Volume = 0.2 x 22.4 = 4.48 litres.

Question 2.

(i) Write an equation for the reaction that takes place at A:

(a) OH- - e- gives OH ; 4OH gives 2H2O + O2

(b) The gas is oxygen. It rekindles a glowing splinter (or turns alkaline pyrogallol solution brown).

(c) Hydrogen (at the cathode).

(d) Pure water is a very poor conductor of electricity because it has very few ions. Adding a little dilute sulphuric acid supplies ions and makes the water a good conductor.

(e) Oxygen : hydrogen = 1 : 2.

(ii)

(a) CHCl3 + Cl2 gives CCl4 + HCl (in diffused sunlight)

(b) Al2O3.2H2O + 2NaOH gives 2NaAlO2 + 3H2O

(c) ZnO + 2NaOH gives Na2ZnO2 + H2O

(d) 3Cu + 8HNO3 gives 3Cu(NO3)2 + 4H2O + 2NO

(e) NaNO3 + H2SO4 gives NaHSO4 + HNO3 (below 200 degrees C, conc. H2SO4)

(iii) Choose the ODD term out from each of the following set of terms. Mention the category to which the remaining three belong:

(a) CnH2n+1

(b) sodium sulphate

(c) NH3

(d) Steel

(e) NH4Cl

(iv)

(a) Redox - CuO is reduced and carbon is oxidized in the same reaction

(b) Reduction - Gain of electrons

(c) Electrolytic dissociation - A molten electrolyte splits into ions

(d) Oxidation - Loss of electrons

(e) Ionization - A covalent compound forms ions in water

(v)

(a)

1. HO-C(=O)-CH2-CH2-CH3 (a carboxylic acid with four carbon atoms): butanoic acid (also accepted: butan-1-oic acid)

2. The structure shows a chain of carbon atoms in full structural form, which is CH3-CH(CH3)-CH2-CH2-CH3: 2-methylpentane. The longest chain has 5 carbons and the methyl group is on carbon 2

(b)

1. Diethyl ether (C2H5-O-C2H5)

H H H H | | | | H — C — C — O — C — C — H | | | | H H H H

2. Isopentane (2-methylbutane, CH3-CH(CH3)-CH2-CH3)

         H      H      H      H

          |        |        |        |

H — C — C — C — C — H

          |        |        |        |

         H       |       H      H

                   |

         H — C — H

                   |

                  H

3. Propanone (CH3-CO-CH3)

         H      O      H

          |       ||        |

H — C — C — C — H

          |                |

         H              H

Question 3.

Section - B

(i) The non-metal P is in group 16 (for example sulphur, giving hydrogen sulphide, H2S). It has 6 valence electrons and needs 2 more to complete its octet, so it shares one electron with each of two hydrogen atoms.

          ××                                      ××

H• + ×P× + •H   →   H •× P ו H

          ××                                      ××

(• = electron of hydrogen, × = electron of P.) Two single covalent bonds form. P has two shared pairs and two lone pairs, so it has an octet; each hydrogen has a duplet.

(ii)

(a) a yellow oily liquid (nitrogen trichloride) is formed, which is explosive. NH3 + 3Cl2 gives NCl3 + 3HCl.

(b) reddish-brown fumes of nitrogen dioxide are evolved. The residue (zinc oxide) is yellow when hot and white when cold. 2Zn(NO3)2 gives 2ZnO + 4NO2 + O2.

(iii)

(a) B is copper sulphate pentahydrate, CuSO4.5H2O.

(b) The dehydrating property of concentrated sulphuric acid. It removes the water of crystallisation, so the blue salt becomes white anhydrous copper sulphate.

(c) CuSO4.5H2O gives CuSO4 + 5H2O (in the presence of conc. H2SO4). The colourless neutral vapour is water vapour.

(iv)

(a) N2O

(b) N2O + H2O gives 2NOH

(c) 2NOH + H2SO4 gives N2SO4 + 2H2O, so the product is N2SO4 (the sulphate of N, that is, sodium sulphate).

Question 4.

(i)

(a) carbon (graphite).

(b) magnalium.

(c) calcination.

(ii)

(a) X - pH 2 is an acid, and dilute acids release SO2 from sulphites: Na2SO3 + H2SO4 gives Na2SO4 + H2O + SO2.

(b) Z - pH 13 is an alkali, and alkalis release ammonia from ammonium salts: NH4Cl + NaOH gives NaCl + H2O + NH3.

(c) Y - pH 7 is neutral.

(iii)

(a) R is ferric chloride, FeCl3. A reddish-brown precipitate of ferric hydroxide shows that the iron is in the +3 state.

(b) FeCl3 + 3NaOH gives Fe(OH)3 + 3NaCl. So P = NaCl and Q = Fe(OH)3.

(c) The reddish-brown precipitate remains insoluble in excess sodium hydroxide.

Question 5.

(i)

M2P MP Molar mass (2 x 14) + 16 = 44 g 14 + 16 = 30 g Moles in 20 g 20 / 44 = about 0.45 mol 20 / 30 = about 0.67 mol

Therefore, M2P has a lesser number of moles than MP.

(ii)

(a) No. Both metals dissolve in hot concentrated NaOH and liberate hydrogen gas, which burns with a pop sound. Zn + 2NaOH gives Na2ZnO2 + H2, and 2Al + 2NaOH + 2H2O gives 2NaAlO2 + 3H2.

(b) Yes. With zinc nitrate, a white precipitate is formed which dissolves in excess ammonium hydroxide. With lead nitrate, a white precipitate is formed which remains insoluble in excess ammonium hydroxide.

(iii)

A: Zn + H2SO4 (dil.) gives ZnSO4 + H2

B: Zn + S gives ZnS (on heating)

C: ZnSO4 + 2NaOH gives Zn(OH)2 + Na2SO4 (or with ammonium hydroxide: ZnSO4 + 2NH4OH gives Zn(OH)2 + (NH4)2SO4)

(iv)

(a) Group 17, Period 3. It has 7 valence electrons (group = 10 + 7 = 17) and 3 shells (period 3).

(b) Less. P has only two shells and Q has three, so P is smaller.

Question 6.

(i)

(a) P = ammonia. 3CuO + 2NH3 gives 3Cu + 3H2O + N2 (ammonia is the reducing agent).

(b) Q = oxygen. 4FeS2 + 11O2 gives 2Fe2O3 + 8SO2.

(c) R = oxygen. 4NH3 + 3O2 gives 2N2 + 6H2O.

(ii)

(a) 252 g = 1 mole, so 126 g = 126 / 252 = 0.5 moles.

(b) Molar mass of Cr2O3 = (2 x 52) + (3 x 16) = 152 g. 252 g of ammonium dichromate gives 152 g of Cr2O3, so 126 g gives 152 x 126 / 252 = 76 g.

(c) 252 g of ammonium dichromate gives 22.4 litres of N2, so 126 g gives 22.4 x 126 / 252 = 11.2 litres.

(iii)

(a) Test tube B. Sodium chloride does not react with NaOH, but ammonium chloride does.

(b) Ammonia (NH3).

(c) Greenish-yellow.

(d) NH4Cl + NaOH gives NaCl + NH3 + H2O.

Question 7.

(i) The acidic gaseous product is carbon dioxide. Ratio of methane to carbon dioxide is 1 : 1.

CH4 + 2O2 gives CO2 + 2H2O

(ii)

P (11 protons) has the configuration 2, 8, 1: it loses 1 electron to form P+. Q (8 protons) has the configuration 2, 6: it gains 2 electrons to form Q2-. Two P+ ions balance one Q2- ion, so the formula is P2Q. Molecular mass = (2 x 23) + 16 = 46 + 16 = 62, so 1 mole of the compound = 62 g.

(iii)

(a) CaC2 + 2H2O gives Ca(OH)2 + C2H2

(b) S + 6HNO3 (conc.) gives H2SO4 + 6NO2 + 2H2O

(c) C2H5COONa + NaOH gives C2H6 + Na2CO3 (heat, CaO)

(iv)

(a) Esterification. CH3COOH + C2H5OH gives CH3COOC2H5 + H2O

(b) Concentrated sulphuric acid acts as a dehydrating agent. It absorbs the water formed, which pushes the reaction towards the ester (it also acts as a catalyst).

(c) A sweet, fruity smell is obtained due to the ester, ethyl ethanoate.

Question 8.

(i)

(a) The oxide ZO shows Z has a valency of 2.

(b) Group 2 (alkaline earth metals).

(c) Z(OH)2. ZO + H2O gives Z(OH)2.

(ii)

(a) Ammonium ion

Nitrogen (2, 5) shares three electrons with three hydrogen atoms. Its remaining lone pair is donated to an H+ ion (no electrons), forming a coordinate bond shown by an arrow from N to H+.

H •× [ H •× N ו H ]+ ×× ↓ H

(• = electron of H, × = electron of N. The arrow marks the co-ordinate bond N to H+.)

(b) Nitrogen Molecule

Each nitrogen atom (2, 5) shares three electrons with the other, forming a triple bond. Each atom keeps one lone pair.

ו ××N ו N•• ו

(iii)

(a) G - Ethene adds bromine: CH2=CH2 + Br2 gives CH2Br-CH2Br.

(b) D - It has the -OH group.

(c) E - Butane and 2-methylpropane both have the formula C4H10 but different structures.

(d) C - Propene is an alkene (CnH2n), like ethene.

We hope this ICSE Class 10 Chemistry Solved Specimen Paper 2027 helped you understand the paper pattern and prepare with more confidence for your board exams.

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