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.(g) (i) State ‘Le Chatelier’s principle’.
(ii) Using Le Chatelier’s principle, predict the effect of increasing pressure on the following equilibrium.
N2(g) + 3H2(g) ⇋ 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.