Majority of the candidates that attempted this question performed poorly.

In (a)(i) and (ii) most candidates could not correctly defined biotechnology and biagas and state their application

In (b) candidates lost marks for not writing the emzymes while other did not write out the process sequentially.  In (c) most candidates gave examples of heavy and fine chemical but incorrectly define them.

In (d) majority of the candidates were able to arrange HCl; O2; Cl2; in increasing order of deviation from the ideal gas behaviour.

The expected answers were:

(a)        (i)         I.          Biotechnology is the use of biological processes/living  organisms  to
                                     make products for human use.
                                                                                                                         
II.        Biogas is a fuel obtained from organic waste through the process of anaerobic decomposition.    

(ii)        Production of drugs (medical) fertilizer, waste management, production of kenkey, fufu, garri, burukutu/any food or beverage produced from fermentation (domestic), industrial application etc.

  ALTERNATIVE
                                                                                                                          
(b)        (i)     Yeast is added to sugar cane juice.  Left to stand (at room temperature)
                      (for few days) to ferment.  The mixture is distilled to obtain ethanol.

            (ii)     Carbon (IV) oxide

           (iii)      -     in aerated drinks;
                       -     as fire extinguisher;
                       -     coolant/refrigerant;
                       -     solvay process;
                       -     synthesis of Na2CO3.

(iv)       Ethanol from cane sugar is renewable because it is from plants which can be cultivated continuously.  
            Ethanol from petroleum is non-renewable because it is from a source which can get exhausted.
                                                                                                                                   
(c)                    Heavy chemicals are chemicals used extensively in industries and are
produced in very large quantities.  
            Fine chemicals are chemicals produced in small quantities for specific purposes     
            and to a very high degree of purity.   

 

            Heavy chemical – H2SO4, NaOH, NH3, Ca CO3, HNO3, HCl, NaCO3, bleaching
            powder, metals (iron, tin, aluminum, copper, zinc).
                           
            Fine chemical

• laboratory/analytical reagents, drugs, dyes, perfumes, photographic reagents, additives, cosmetics.       

                                                                                                                                           
(d)                   O2, Cl2  HCl Increasing order to deviation  
                        The extent of deviation depends on intermolecular forces.   
                        HCl is polar and will have a greater intermolecular attraction than oxygen and                                chlorine. The molar mass of chlorine is greater than that of oxygen hence stronger
                        vander waals forces than oxygen.