11.If the coliform bacteria is present in a sample of water, then the coliform test to be conducted is i) presumptive coliform test ii) confirmed coliform test iii) completed coliform test The correct answer is

12.The hourly variation factor is usually taken as

13.Alkalinity in water is expressed as milli-grams per litre in terms of equivalent

14.The most common cause of acidity in water is

15.Ground water is usually free from