Chemistry — Suggested Paper 1

1(i). Which of the following options has all the compounds which are members of the same homologous series?

1(ii). Which statement about conduction of electricity is correct?

1(iii). Given below are four ions: Cl⁻, Li⁺, Al³⁺, K⁺ Identify the pair of ions which have the same electronic configuration. [Atomic number: Cl = 17, Li = 3, Al = 13, K = 19]

1(iv). If the pH of a solution is ‘2’, then solution is a:

1(v). What volume of carbon dioxide is produced at STP when 5 litres of propane is burnt completely according to the equation given below? C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

1(vi). The compound that has the highest melting point amongst the following is:

1(vii). The acid which is least volatile is:

1(viii). Which of the following compounds neither dissociate not ionise in water?

1(ix). A student added excess of sodium hydroxide solution to each of the salt solution. An insoluble precipitate formed was observed in:

1(x). In the laboratory preparation, HCl gas is dried by passing through:

1(xi). On passing ammonia gas over heated copper oxide for some time, a reddish-brown residue is left behind. What property of ammonia is demonstrated here?

1(xii). The gas formed, when calcium bisulphite reacts with dilute HNO₃:

1(xiii). Rita added dilute hydrochloric acid to four metals. She recorded her observations in the table given below. While noting her observations she made some errors. Which observation(s) made by Rita is/are correct?

1(xiv). If the molecular formula of an organic compound is C₁₀H₁₈ it is:

1(xv). Solid sodium chloride does not conduct electricity as:

2(i)(i). The formula that represents the simplest ratio of the various elements present in one molecule of the compound.

2(i)(ii). The substance that releases hydronium ion as the only positive ion when dissolved in water.

2(i)(iii). The tendency of an atom to attract electrons towards itself when combined in a covalent compound.

2(i)(iv). The process by which certain ores, specially carbonates, are converted to oxides in the absence of air.

2(i)(v). The covalent bond in which the electrons are shared equally between the combining atoms.

2(ii)(a). Name the substance X added through the thistle funnel by the student.

2(ii)(b). Write a balanced equation for the reaction occurring between Aluminium nitride and substance X.

2(ii)(c). Identify the substance Y.

2(ii)(d). State the function of Y.

2(ii)(e). Why could the student not collect ammonia gas at the end of the experiment?

2(iii)(a). During electroplating the iron cup is placed at the cathode. Why?

2(iii)(b). Name the ion that must be present in the electrolyte.

2(iii)(c). State one condition that is necessary to ensure that the deposit is smooth, firm and even.

2(iii)(d). Write the reaction taking place at the cathode.

2(iii)(e). What change would you observe at the anode?

2(iv)(a). The group obtained by removing one hydrogen atom from the parent alkane.

2(iv)(b). Two metal plates or wires through which the current enters and leaves the electrolytic cell.

2(iv)(c). The amount of substance which contains the same number of units as the number of atoms in carbon-12.

2(iv)(d). The tendency of an atom to pull a shared pair of electrons towards itself in a compound.

2(iv)(e). The formula which represents the simplest ratio between the atoms of elements present in a compound.

2(v)(i). K, Pb, Ca, Zn. (In the increasing order of the reactivity)

2(v)(ii). Mg²⁺, Cu²⁺, Na¹⁺, H¹⁺ (In the order of preferential discharge at the cathode)

2(v)(iii). Li, K, Na, H (In the decreasing order of their ionization potential)

2(v)(iv). F, B, N, O (In the increasing order of electron affinity)

2(v)(v). Ethane, methane, ethene, ethyne. (In the increasing order of the molecular weight) [H = 1, C = 12]

3(i)(a). Bronze

3(i)(b). Fuse metal

3(ii)(a). Ammonium ion

3(ii)(b). A molecule of nitrogen

3(iii)(a). Ethene from ethanol

3(iii)(b). Ethyne from calcium carbide

3(iii)(c). Monochloromethane from methane

3(iv)(a). When a crystalline solid 'P' is warmed with concentrated H₂SO₄ and copper turnings a reddish brown gas is released.

3(iv)(b). When few drops of dilute sulphuric acid is added to Salt 'R' and heated, a colourless gas is released which turns moist lead acetate paper silvery black.

3(iv)(c). When few drops of barium nitrate solution is added to the salt solution 'Q', a white precipitate is formed which is insoluble in HCl.

4(i)(a). the cation present and

4(i)(b). the anion present in the salt given for identification.

4(ii)(a). Carbon tetrachloride is a ............... [polar / non-polar] covalent molecule.

4(ii)(b). During electrolysis of acidulated water, the gas liberated at the anode is ............... [oxygen / hydrogen].

4(iii). Ammonia burns in oxygen as shown below. 4NH₃ + 3O₂ → 2N₂ + 6H₂O If 240 cc of ammonia is burnt in 300 cc of oxygen, find out the composition of the resultant gaseous mixture at room temperature.

4(iv)(a). Write the formula of the compound formed between: 1. A and B 2. D and C

4(iv)(b). Which of the above elements will exhibit catenation?

5(a). Baeyer's process is used to concentrate bauxite ore to alumina. Give balanced chemical equations for the reaction taking place for its conversion from bauxite to alumina.

5(c). Match the gases given in column I to the identification of the gases mentioned in column II:

5(b)(i). pH of acetic acid is greater than dilute sulphuric acid. So acetic acid contains ............... concentration of H⁺ ions. (greater, same, low)

5(b)(ii). The indicator which does not change colour on passage of HCl gas is ................ (methyl orange, moist blue litmus, phenolphthalein)

5(b)(iii). The acid which cannot act as an oxidizing agent is ................ (conc. H₂SO₄, conc. HNO₃, conc. HCl)

6(a)(i). Write the balanced chemical equation to prepare ammonia gas in the laboratory by using an alkali.

6(a)(ii). State why concentrated sulphuric acid is not used for drying ammonia gas.

6(a)(iii). Why is ammonia gas not collected over water?

6(b)(i). Name the acid used for the preparation of hydrogen chloride gas in the laboratory. Why is this particular acid preferred to other acids?

6(b)(ii). Write the balanced chemical equation for the laboratory preparation of hydrogen chloride gas.

6(c)(i). Why is direct absorption of hydrogen chloride gas in water not feasible?

6(c)(ii). What arrangement is done to dissolve hydrogen chloride gas in water?

6(d)(i). What is the cathode made up of?

6(d)(ii). Write the reaction that takes place at the anode.

7(a)(i). Copper sulphate

7(a)(ii). Zinc carbonate

7(a)(iii). Ammonium sulphate

7(b)(i). An alkaline earth metal present in group 2 and period 3.

7(b)(ii). A trivalent metal used to make light tools.

7(b)(iii). A monovalent non-metal present in fluorspar.

7(c)(i). What do you observe at the cathode and anode respectively?

7(c)(ii). Name the cation that remains as a spectator ion in the solution.

7(c)(iii). Which equation for the reaction at the anode is correct? 1 Ni ⟶ Ni²⁺ + 2e⁻ 2 Ni + 2e⁻ ⟶ Ni²⁺ 3 Ni²⁺ ⟶ Ni + 2e⁻ 4 Ni²⁺ + 2e⁻ ⟶ Ni

8(i)(a). Sulphuric acid acts as a dehydrating agent.

8(i)(b). Ammonia reacts with chlorine to give ammonium chloride and nitrogen.

8(ii)(a). The compound on heating produces a colourless, odourless gas which turns lime water milky and has no effect on acidified potassium dichromate solution.

8(ii)(b). The solution of the compound which on treating with concentrated sulphuric acid and freshly prepared ferrous sulphate solution produces a brown ring.

8(iii)(a). will react with Magnesium to liberate hydrogen gas?

8(iii)(b). will liberate ammonia gas when it reacts with ammonium chloride?

8(iii)(c). will contain molecules as well as ions?

8(iv). The following table is related to an Industrial process of an acid. Identify (a), (b) and (c).