Engineering Chemistry
Question Bank
Unit I
Water Technology
1) Explain the causes of scales in boiler. Give two disadvantages and two methods of prevention.
[6]
2) Define Reverse Osmosis. Give its two advantages & two limitations. [3]
3) Explain Zeolite process for softening of water with figure, process, ion exchange and
regeneration reaction, two advantages. [6]
4) State the causes of foaming when it takes place in boiler and give remedial measures for its
prevention. [3]
5) What are scales & sludges? Explain the causes of scale formation in boiler. [6]
6) Explain reverse osmosis process with figure. [3]
7) What is hardness of water? Explain the procedure of EDTA method for determination of total
hardness. Give formula for total hardness and reactions involved. [6]
8) Give cation & anion exchange reaction for deionisation of water containing MgCl₂. [3]
9) Describe Deionisation method of water softening with ion-exchange and regeneration reactions.
[6]
10) What is hardness of water? Define temporary and permanent hardness. [3]
11) What is reverse osmosis? Describe the process with labelled diagram. [3]
12) Give exchange reactions of zeolite with following salt. [3]
i) Ca(HCO₃)₂ ii) MgCl₂ iii) CuSO₄
13) What are zeolites? Give reactions for: [3]
i) Removal of Ca⁺⁺ and Mg⁺⁺
ii) Regeneration of exhausted zeolite
14) What are different types of impurities in water. Explain any two in detail. [3]
15) Define Desalination of water. Explain reverse osmosis process for desalination of water with
neat labelled diagram. [6]
, Numericals
1) 25 ml of hard water sample required 11.2 ml of 0.01 M EDTA to reach the end point. 25
ml of the same water sample after boiling and filtration required 7.9 ml of the same EDTA
to reach the end point. Calculate total, temporary and permanent hardness of water. [3]
2) 25 ml water sample requires 3.7 ml of 0.01 N HCl up to phenolphthalein end point and 7.4
ml up to methyl orange end point during the titration. Calculate types and amount of
alkalinity present in water. [3]
3) The hardness of 50,000 litres of a water sample was removed by passing it through a zeolite
softener. The softener required 250 litres of NaCl containing 100 gm/lit of NaCl for
regeneration. Calculate hardness of water. [3]
4) An exhausted zeolite was regenerated by 150 litre of NaCl having strength 150 gm/liter.
How many litres of hard water having hardness 400 ppm as CaCO₃ can be softened by this
softener? [3]
5) 100 ml of water sample on titration with N/50 HCl required 7.6 ml for phenolphthalein end
point & 15.2 ml for total alkalinity reading. Identify type & amount of alkalinity present in
water sample. [3]
6) Water sample is not alkaline to phenolphthalein. However, 25 ml of this water sample on
titration required 4.5 ml 0.02 N HCl for methyl orange end-point. Determine the type and
amount of alkalinity present in water. [3]
7) 25 ml of water sample required 8.8 ml of 0.01 M EDTA to reach the end-point. 25 ml of
the same water sample after boiling and filtration required 6.5 ml of the same EDTA
solution to reach the end-point. Calculate total and permanent hardness of the water sample.
[3]
8) 100 ml of an alkaline water sample requires 5.2 ml of 0.02 N HCl up to phenolphthalein
end point and 15.8 ml for methyl orange end point. Find the type and amount of alkalinity
in water sample. [3]
9) 50 ml of water sample require 18 ml of 0.05 M EDTA during titration. Whereas 50 ml of
boiled water sample require 12.5 ml of same EDTA in the titration. Calculate total,
temporary and permanent hardness of water sample. [3]
10) A zeolite bed exhausted by softening 4000 lit. of water requires 10 litres of 15% NaCl
solution for regeneration. Calculate the hardness of water sample. [3]
11) 100 mL water consumed 5.2 mL of 0.02M HCl up to phenolphthalein end point and 15.8
mL at methyl orange end point in titration. Find amount and types of alkalinity in water.
[3]
12) 50 mL water sample required 18 mL 0.05M EDTA in a hardness determination experiment.
Whereas 50 mL of the same water after boiling consumed 9 mL 0.05M EDTA. Calculate
Total, Permanent and Temporary Hardness of water sample. [3]
Question Bank
Unit I
Water Technology
1) Explain the causes of scales in boiler. Give two disadvantages and two methods of prevention.
[6]
2) Define Reverse Osmosis. Give its two advantages & two limitations. [3]
3) Explain Zeolite process for softening of water with figure, process, ion exchange and
regeneration reaction, two advantages. [6]
4) State the causes of foaming when it takes place in boiler and give remedial measures for its
prevention. [3]
5) What are scales & sludges? Explain the causes of scale formation in boiler. [6]
6) Explain reverse osmosis process with figure. [3]
7) What is hardness of water? Explain the procedure of EDTA method for determination of total
hardness. Give formula for total hardness and reactions involved. [6]
8) Give cation & anion exchange reaction for deionisation of water containing MgCl₂. [3]
9) Describe Deionisation method of water softening with ion-exchange and regeneration reactions.
[6]
10) What is hardness of water? Define temporary and permanent hardness. [3]
11) What is reverse osmosis? Describe the process with labelled diagram. [3]
12) Give exchange reactions of zeolite with following salt. [3]
i) Ca(HCO₃)₂ ii) MgCl₂ iii) CuSO₄
13) What are zeolites? Give reactions for: [3]
i) Removal of Ca⁺⁺ and Mg⁺⁺
ii) Regeneration of exhausted zeolite
14) What are different types of impurities in water. Explain any two in detail. [3]
15) Define Desalination of water. Explain reverse osmosis process for desalination of water with
neat labelled diagram. [6]
, Numericals
1) 25 ml of hard water sample required 11.2 ml of 0.01 M EDTA to reach the end point. 25
ml of the same water sample after boiling and filtration required 7.9 ml of the same EDTA
to reach the end point. Calculate total, temporary and permanent hardness of water. [3]
2) 25 ml water sample requires 3.7 ml of 0.01 N HCl up to phenolphthalein end point and 7.4
ml up to methyl orange end point during the titration. Calculate types and amount of
alkalinity present in water. [3]
3) The hardness of 50,000 litres of a water sample was removed by passing it through a zeolite
softener. The softener required 250 litres of NaCl containing 100 gm/lit of NaCl for
regeneration. Calculate hardness of water. [3]
4) An exhausted zeolite was regenerated by 150 litre of NaCl having strength 150 gm/liter.
How many litres of hard water having hardness 400 ppm as CaCO₃ can be softened by this
softener? [3]
5) 100 ml of water sample on titration with N/50 HCl required 7.6 ml for phenolphthalein end
point & 15.2 ml for total alkalinity reading. Identify type & amount of alkalinity present in
water sample. [3]
6) Water sample is not alkaline to phenolphthalein. However, 25 ml of this water sample on
titration required 4.5 ml 0.02 N HCl for methyl orange end-point. Determine the type and
amount of alkalinity present in water. [3]
7) 25 ml of water sample required 8.8 ml of 0.01 M EDTA to reach the end-point. 25 ml of
the same water sample after boiling and filtration required 6.5 ml of the same EDTA
solution to reach the end-point. Calculate total and permanent hardness of the water sample.
[3]
8) 100 ml of an alkaline water sample requires 5.2 ml of 0.02 N HCl up to phenolphthalein
end point and 15.8 ml for methyl orange end point. Find the type and amount of alkalinity
in water sample. [3]
9) 50 ml of water sample require 18 ml of 0.05 M EDTA during titration. Whereas 50 ml of
boiled water sample require 12.5 ml of same EDTA in the titration. Calculate total,
temporary and permanent hardness of water sample. [3]
10) A zeolite bed exhausted by softening 4000 lit. of water requires 10 litres of 15% NaCl
solution for regeneration. Calculate the hardness of water sample. [3]
11) 100 mL water consumed 5.2 mL of 0.02M HCl up to phenolphthalein end point and 15.8
mL at methyl orange end point in titration. Find amount and types of alkalinity in water.
[3]
12) 50 mL water sample required 18 mL 0.05M EDTA in a hardness determination experiment.
Whereas 50 mL of the same water after boiling consumed 9 mL 0.05M EDTA. Calculate
Total, Permanent and Temporary Hardness of water sample. [3]
