CHEMISTRY

SCIENCE Paper – 2

SECTION I (40 Marks)
Attempt all questions from this Section

Question 1         

(a) Choose the correct answer from the options given below:       [5]
(i) A strong electrolyte from the following is :
A. Acetic acid
B. Oxalic acid
C. Ammonium hydroxide
D. Sodium hydroxide

(ii) Electron affinity is maximum in:
A. Alkali metals
B. Alkaline earth metals
C. Halogens
D. Inert gases

(iii) The main components of brass are :
A. Copper and Zinc
B. Copper and lead
C. Copper and tin
D. Copper and iron

(iv) The drying agent used to dry NH3 is:
A. P2O5
B. conc. H2SO4
C. CaCl2
D. CaO

(v) The general formula of alkynes is:
A. CnH2n–2
B. CnH2n+2
C. CnH2n
D. CnH2n+2O

(b) Write balanced chemical equations for each of the following:      [5]

(i) Catalytic oxidation of ammonia
(ii) Action of concentrated nitric acid on Sulphur.
(iii) Action of concentrated sodium hydroxide on Zinc oxide
(iv) Reaction between acetic acid with ethanol in the presence of concentrated sulphuric acid.
(v) Action of dilute hydrochloric acid on iron.

(c) State any one observation for each of the following:           [5]

(i) Dilute Hydrochloric acid is added to Silver Nitrate solution.
(ii) Concentrated Nitric acid is added to Copper turnings.
(iii) Mixture of Ammonium Chloride and Sodium Hydroxide is heated.
(iv) Ammonium hydroxide solution is added in excess to copper sulphate solution.
(v) NaOH solution is added to calcium nitrate solution.

(d) Rewrite the following by inserting appropriate word / words:          [5]

(i) Magnesium Nitride reacts with water to liberate Ammonia.
(ii) Lead bromide conducts electricity.
(iii) Starch iodide paper turns blue black in the presence of Chlorine.
(iv) Hydrogen chloride molecule contains a covalent bond.
(v) Acid salts are formed by replacement of the ionisable hydrogen ions of the acid by a metallic ion or ammonium ion.

(e) (i) Given: 2C2H6 + 7O2  4CO2 + 6H2O      [5]

2000 cc of O2 was burnt with 400 cc of ethane.
Calculate the volume of CO2 formed and unused O2

(ii) Find the number of moles and molecules present in 7.1 g of Cl2.
(At. Wt. C l = 35.5)

(iii) Calculate the vapour density of ethene [ C =12 , H = 1]

(f) Identify the terms:           [5]
(i) The energy required to remove an electron from valance shell of a neutral isolated gaseous atom.
(ii) The method for the concentration of sulphide ores.
(iii) The property by which carbon bonds with itself to form a long chain.
(iv) A bond formed by a shared pair of electrons with both electrons coming from the same atom.
(v) A substance that conducts electricity in molten or aqueous state.

(g) Arrange the following as per the instruction given in the brackets.         [5]
(i) Li, F, N [increasing order of electronegativity]
(ii) Na, Al , Cl [increasing order of Ionization potential ]
(iii) O2, N2, Cl2 [increasing order of number of covalent bonds]
(iv) Zn2+, Na+, Cu+2 [order of preference of discharge at the cathode]
(v) Br , F , Cl [Decreasing order of atomic radius]

(h) (i) Draw the structural formula for each of the following:       [5]
1. But-1-ene
2. Propanoic acid
3. Ethanol
(ii) Draw the structural isomers of C4H10

SECTION II (40 Marks)
Attempt any four questions from this Section

Question 2

(a) Write balanced equations for following conversions:
Zn CO3 Zn(NO3)2 Zn(OH)2
ZnSO4       [4]

(b) Show the formation of H3O+ using the electron dot diagram.
State the types of bonds present in it. [3]

(c) Distinguish between the following pairs of compounds using the test given within the brackets.
(i) Calcium sulphite and calcium carbonate (using dil. HCl)
(ii) Calcium nitrate and potassium nitrate (using a flame test)
(iii) Lead nitrate solution and Zinc nitrate solution (using an alkali) [3]

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