Assignment

1. 100 mL of a water sample, on titration with N/50 H₂SO₄ using phenolphthalein as indicator, gave the end point when 50 mL of acid were used. Another aliquot of 100 mL of the sample also required 5.0 mL of the acid to obtain the methyl orange end point. What is the type of alkalinity present in the sample?

2. The hardness of 1000 litres of a water sample was completely removed by a zeolite softener. The zeolite required 30 litres of NaCl solution containing 1,500 mg/L of NaCl for regeneration. Calculate the hardness of the water sample.

3. What is alkalinity and why is it important? Discuss.

4. What are the water quality standards for alkalinity?

5. A water sample is not alkaline to phenolphthalein. However, 100 mL of the sample, on titration with N/50 HCl, required 16.9 mL to obtain the end point using methyl orange as indicator. What is the amount of alkalinity present in the sample?