Pt1420 Unit 6 Study Guide

Chemistry Lab Question Bank (2014-2015)
Topic: Introduction

1. What is a standard solution?
2. What is a primary standard solution? Give examples.
3. What is a secondary standard solution? Give examples.
4. What is a link solution?
5. Why is KMnO4 not a primary standard solution?
6. Define equivalent weight?
7. Define end point and equivalence point?
8. Why solutions of HCl and NaOH are not primary standard solutions?
9. How many types of titrations are there? Give examples.
10. Define Molarity and write its formula?
11. Define Normality and write its formula?
12. Write any two indicators which are used in Acid-Base titrations?
13. What is complexometric titration? Give an example.
14. Which indicator is used in the estimation of hardness of
water by EDTA method ?
15. What are pre requisites of a standard solution?
16. Define Redox reaction with an example.
17. Define reducing agent and oxidising agent. Give an example.
18.
Name few indicators used in Redox titrations.
19. Why KMnO4 is acts as a self indicator. Explain it.
20. Find out oxidation states of Mn & Cr in KMnO4 & K2Cr2O7 respectively.

ESTIMATION OF FERROUS IRON BY PERMANGANOMETRY

1. Write FAS/Mohr's salt formula &molecular weight?
2. What are pre requisites of a standard solution?
3. Define primary standard solution? Give examples.
4. Define secondary standard solution? Give examples.
5. Why dil H2SO4 is added in the preparation of standard FAS solution?
6. Why KMnO4 solution needed to be standardised?
7. Why dil H2SO4 is added to FAS solution in standardisation of KMnO4?
8. Write the principle of estimation of iron (II) by permanganometry ?
9. Identify the oxidising &reducing substances in the reaction.
10. Define oxidising agent & give some examples
11. Define reducing agent & give some examples
12. What is a Redox reaction give example?
13. Why KMnO4 acts as self indicator.
14. Write the molecular wt. & equivalent wt. of KMnO4, FAS &H2SO4?
15. How would you calculate the weight of Fe+2 present in the given solution?
16. Can we replace dil. H2SO4 with HCl in this experiment?
17. What is end point colour change during the titration?
18. What is double salt? Give an
example.
19. What is a coordination complex? How it is different from double salt.
20. For a colour solution mark should coincide with--------------------- meniscus.
21. For a colour solution mark should coincide with--------------------- meniscus.
22. Which ion is responsible for colour change?
23. Write the brief procedure of the experiment.
24. Write the steps involved in the experiment.
25. Write the oxidation state of Mn in KMnO4,Fe in FAS, Mn in MnSO4 & Fe in Fe2(SO4)3.
26. Why we are unable to identify the bi products like MnSO4, Fe2(SO4)3,K2SO4 in the reaction.
27. Why we have to shake the solution in preparation of standard FAS solution.

ESTIMATION OF TOTAL HARDNESS OF WATER BY EDTA METHOD

1. Define hardness of water.
2. What is the cause of hardness in water?
3. Categorize the compounds of calcium and magnesium that cause temporary and permanent hardness.
4. What is EDTA?
5. Give the structure of EDTA.
6. Can EDTA be used for removing hardness of water?
7. What is a buffer solution?
8. What is degree of hardness?
9. How do you remove temporary hardness of water?
10. Why is hardness reported in PPM instead of Normality?
11. What is CaCO3 equivalent?
12. How does temporary hardness differ from permanent hardness?
13. What is the function of the buffer solution?
14. What is the permissible degree of hardness of potable water?
15. What is the indicator used in EDTA method?
16. What are the less stable complexes formed in this titration?
17. What is meant by softening of water?
18. Why do we use disodium salt of EDTA?
19. Give the reactions involved in the elimination of temporary hardness?
20. How do you distinguish hard and soft water using a color test?
21. Mention different units to express hardness of water and give their inter-relation?
22. Give the scheme for estimation of hardness of water by EDTA method?
23. Can EDTA distinguish between temporary and permanent hardness.
24. Suggest a method of establishing the amount of permanent hardness in a water sample.
25. What type of titration is involved in this experiment?
26. What is the PH favorable for the formation of complexes?
27. What is the color change at end point?
28. Why do we get wine red color in this experiment?
29. Why blue color is formed at the end point.
30. Give the type and composition of the buffer used in this experiment.
31. What is the principle involved in the color change from wine red to blue?
31. Why CaCO3 is used as a standard for calculating hardness?
32. What is the molecular and equivalent weight of CaCO3?
33. What is the role of EDTA in this titration?

ESTIMATION OF CARBONATE & BICARBONATE IN THE GIVEN SOLUTION USING STANDARDIZED HYDROCHLORIC ACID.

1. What is alkalinity?
2. Which ions impart alkalinity to the natural water?
3. How many types of alkalinity are possible?
4. Why can't we use phenolphthalein for the complete neutralization of carbonate?
5. Can we replace conc. HCl by conc. H2SO4?
6. Which type of titration this experiment belongs to ?
7. What is half-neutralization point?
8. What is the role of methyl orange in this experiment?
9. To calculate the amount of alkalinity why equivalent weight of CaCO3 is included?
10. Justify the need of two indicators?
11. Can OH-, CO3-2, HCO3- exist together?
12. What is the color of the indicators phenolphthalein and methyl orange in acidic and basic medium?
13. Why can't we use only one indicator in estimation of the alkalinity?
14. What is the permissible alkalinity of potable water? 15. Write the reactions involved in this titration.
16. Give the molecular and equivalent weights of carbonate and bicarbonate ions.
17. What are the ions determined by phenolphthalein?

CONDUCTOMETRY
1. Define conductance. What are its units?
2. Define conductivity.
3. What are the different types of conductance?
4. Describe the conductivity cell.
5. Why the electrodes are platinised?
6. How the conductivity meter is calibrated?
7. Why temp. is kept constant?
8. What are the factors influencing conductance?
9. Name some strong and weak electrolytes.
10. Why the conductance of HCl decreases initially when NaOH is added.
11. Give the graph pattern of S.A VS S.B.
12. Why the conductance is not zero at equivalence point.
13. Why the conductance increases after equivalence point in S.A VS S.B.
14. What are the species present at the equivalence point.
15. Give the graph pattern of mixture of acids VS S.B.
16. Which acid gets neutralises first and why in Mixture of acid Vs Strong Base
17. What is common ion effect?
18. What are the species present at the two equivalence points.
19. Why the conductance increases gradually after the first equivalence point.
20. Why the conductance increases rapidly after the second equivalence point
21. What indicator used in the standardisation of NaOH.
22. Write reaction between the oxalic acid and NaOH.
23. What is cell constant? mention its units.
24. What is the difference between equivalence and end point?

COLORIMETER 1. What principle is involved in colorimetry?
2. Write the difference between colorimeter and calorimeter?
3. State Beer-Lambert’s law.
4. What is optical density?
5. Mention the units of optical density.
6. Write the use of filter in colorimeter.
7. Define monochromatic light.
8. Why line passes through origin when a graph plotted between O.D and Concentration?
9. Does each filter gives monochromatic light?
10. Can we find out the concentration of Acetic acid using colorimeter?
11. What is the optical density of hydrochloric acid containing phenolphthalein indicator?
12. Can we find out the concentration of sodium hydroxide having phenolphthalein indicator?
13. Why can’t we get same optical density for some concentration of KMnO4 after 10 days of the same solution and temperature?
14. Can we determine the amount of iron in steel using colorimeter? 15. Can we determine the amount of iron in cement using colorimeter?
16. Can we determine the amount of copper in brass using colorimeter?
17. Write the mathematical expression of Beer-Lamberts law
18. Mention the factors which change the optical density of solution.
19. Why quartz make cuvvets are preferable in determination of optical density?
20. Do you get a linear plot passing through origin for OD vs concentration for a colored solution of concentration greater than 2M?