steel depend upon the ……….. .
(c) Ammonia gas has a characteristic ………. smell.
(d) Hydrogen sulphide has weak ………. properties.
(e) Halogens have essential electronic structure of ………. .
(f) In the reaction with ammonia, boron trifluoride behave as an ………. .
(g) The IUPAC name of di-methyl methylene is ………. .
- Select the correct word(s) given in the bracket. (7 marks)
(a) Proteins is ( polymer, copolymer, monomer).
(b) The molecule of (NH3, ClF3, BCl3) does not deviate octet rule.
(c) The volume of the gas decreases (rapidly, slowly, regularly) with regular decrease of temperature.
(d) The anhydrous sodium carbonate can be used as a (an) (indicator, catalyst, primary standard)
(e) Faraday’s laws express the (qualitative, quantitative, volumetric) results of electrolysis.
(f) Oxidation number of sulphur in H2SO3 is ( +6,+4,-2) .
(g) Light is a source of (force, pressure, energy). - Match each of the items in List A with the appropriate items in the list B. (7 marks)
List A List B
(a) Neutralization (i) it dissolves in noble metal gold
(b) Alum (ii) CaO Cl2.2 H2O
(c) Ammonium iron (II) sulphate (iii) show allotropy
(d) Aqua-regia (iv) reaction between any acid and a base
(e) Sulphur (v) dissociation constant of the indicator
(f) Bleaching powder (vi) K2SO4. Al2(SO4)3.24 H2O
(g) Kin (vii) (NH4)2 SO4.FeSO4.6H2O - Define the following terms. (8 marks)
(a) Electron affinity
(b) Gay-lussac’s law of oxidation number
(c) Molarity
(d) Electrolysis
(e) Reduction in terms of oxidation number
(f) A catalyst
(g) Chemical energetics
(h) An acid according to Lewis theory
SECTION (B) - Answer ALL questions. (12 marks)
(a) What of chemical bond is formed between 3NH3 and H+ ion? Write down the electron dot-cross formula
of the ion formed.
(b) Define ‘ Relative density of a gas’. What is the relative density of nitrogen oxide? (O =16, N=14).
(c) Write the balanced equation in words and symbols for the preparation of aluminium oxide (alumina).
(d) Write down the reactions at the cathode and anode for the electrolysis of dilute sulphuric acid using
platinum electrodes.
(e) From the following equation, identify oxidizing and reducing agents .Give reason for your answer.
2H2O + 2Br2 → O2 + 4HBr
(f) Which elements (s) N or P or K is not suitable for seed bearing and for leaf crops?
Answer any FIVE questions. (20 marks)
(a) What volume at STP of oxygen and what mass of aluminium will be liberated during electrolysis by a
charge of one Faraday?
(b) Write balance equations for the following reactions.
(i) H2S + KMnO4 + H2SO4 → MnSO4 + K2SO4 + H2O + S
(ii) CuO + H2 → Cu + H2O
(c) An atom A has an atomic number of 12 whereas an atom B has an atomic number of 17.Write down
(i) essential electronic structures
(ii) positions in the periodic table
(iii) types of electrons and
(iv) type of bond that is formed between A and B.
(d) Write equations in words and symbols for the following reactions.
(i) Dinitrogen oxide reacts with carbon.
(ii) Concentrated nitric acid reacts with magnesium.
2NH3(g)
(h) (i) Describe the elements required by plants.
(ii) Give the monomer structure and uses of PS.Answer any FOUR questions. (32 marks)
(a) (i) Define buffer solution.
(ii) Calculate the pOH of a buffer solution containing 0.2 mole of ethanoic acid (pKa=3.8) and 0.05 mole
of sodium ethanoate per 200 cm3 of solution.
(b) (i) Define the electrical energy and the mechanical energy.
(ii) Calculate the heat of combustion of butane gas (C4H10) if its heat of formation is -124 kJ mol-1.The
Heats of formation of CO2 (g) and H2O(l) are -395 kJ mol-1 and -287 kJ mol-1, respectively.
(c) Write down the complete equations of the following equations.
(i) CH3-CH2-COONa + NaOH → ?(ii) CH3-CH2-OH H2SO4(conc) ? (iii) CH3-CH2-OH Al2O3 ? (iv) CH3-CH2-Cl + KOH ethanol ?(d) (i)What happens when ozonized oxygen is passed into ethane in chloroform and the product is
decomposed by water?
(ii) What happens when propene is