HOW DO ENZYMES BRING ABOUT SUCH HIGH RATES OF CHEMICAL CONVERSIONS?

(a) How will you bring about the following conversions : (i) Toluene to benzaldehyde (ii) Ethanenitrile to ethanoic acid (B) Identify A, B, C and D in the following reactions :'

How will you bring about the following changes :

How does pH affects the rate of enzyme activity?