1 In the reaction of potassium permanganate and iron salt in acidic medium, how many moles of manganese reacted with iron?



2 moles of Mn with 1 mole of Fe
1 mole of Mn with 5 moles of Fe
1 mole of Mn reacts with 1 mole of Fe
5 moles of Mn reacts with 1 mole




2 Which of the following is not correct about potassium permanganate when used in titrimetric analysis?


It is a primary standard
It acts in acidic medium
It acts in basic medium
It requires the use of an external indicator




3 When starch is used in iodiometric titration, the colour changes from -----------


Red to blue at the end point
Blue black to colourless at the end point
Colourless to orange at the end point
Light yellow to brown at the end point




4 What is the oxidation of chromium in potassium dichromate?


+1


+4


+6


+7





5 Which the following is not a primary standard


Potassium permanganate
Oxalic acid
Ammonium iron (II)sulphate
Sodium oxalate




6 A standard solution is a ----------------.


Dilute solution
Solution of known concentration
Concentrated solution
Measured solution




7 When a substance is not available in a pure form, its solution can be standardized by ---------------.


Re- crystallizing the substance and diluting it
Titrating againt a substance of unknown concntration
Titrating against a substance of known concentration
Preparing a new solution of the substance




8 A pure substance could be described as -----------.


A white crystalline sample
A sample with little impurities
A sample which maintains its physical appearance with time
A sample which does not change its chemical composition during storage




9 On heating a substance prior to weighing, it is placed --------------.


On the laboratory desk
In water
In a fume hood
In a dessicator




10 Heating sodium bicarbonate before its use as a standard expels


Carbon dioxide only
Water and carbon dioxide
Water only
Impurities




11 3.47g sodium carbonate was dissolved in a 250millilitre standard flask. What is the concentration of the resulting solution


0.13M
0.52M
0.66M
0.40M




12 One of the following is not a proper way of preparing 0.025M solution from 1.00M stock solution.


2.5 mL of stock solution is diluted to 100mL
25 mL of stock solution is made up to 1000mL
12.5 mL of the stock solution is made up to 500mL
12.5 mL of the stock solution is made up to 750mL




13 All the following apparatus are needed for the preparation of a solution of hydrochloric acid, HCl, from the concentrated solution EXCEPT --------------.


Measuring cylinder
Burette
Crucible
Volumetric flask




14 If
15cm 3
of 10.25M HCl solution is made up to volume in a 500 Ml volumetric flask, what will be its new concentration?


0.306M
3.06M
5.13M
0.52M




15 In the preparation of a solution, it is advisable to shake the mixture well. This is necessary to ----------------.


Ensure that the solution precipitates out very well
Induce air bubbles in the solution
Produce a homogenous solution
Facilitate use of lesser volume of water




16 To dilute an acid with water, acids are added to water and not water to acid because -----------------.


Acids are more vicourse than water
Water is weaker than acid
Dissolution of acid in water is exothermic which could be explosive
Acids will not dissolve in water if done wrongly




17 During standardization of HCl with sodium carbonate titration, the pipette is rinsed with distilled water and thereafter with ------------.


the HCl solutin
The methyl orange indicator
the
Na 2 CO 3
solution
More water




18 In a standardization titration involving hydrochloric acid and sodium carbonate, a student recoirded the following results for the volume of hydrochloric acid used against 10.00mL of the sodium carbonate solution : 15.60; 14.50; 14.70 aqnd 14.20. What is


14.60mL
14.75mL
14.47mL
14.00mL




19 In a standardization titration involving hydrochloric acid and sodium carbonate, a student recoirded the following results for the volume of hydrochloric acid used against 10.00mL of the sodium carbonate solution : 15.60; 14.50; 14.70 aqnd 14.20. If the c


1.02 Ml
1.03mL
1.07mL
1.04M




20 In titration, the experimentally determined stoichiometric point of the titration is referred to as--------------.


Flash point
Critical point
Equivalence point
stop point

Mike--How can I help you with this assignment? I see 40 questions (20 here and 20 on the next one) and I'm not inclined to spend the rest of the day doing those when you've shown no effort on your part. If you will pick them out one at a time and tell me what you don't understand about them (one at a time) and what you've tried, perhaps we can work our way through some of them. If you have already worked them and you're just checking your answers, please post your work for EACH one (not just the answer) and I shall be happy to check your work for you.

thanks for the reply, I just want to confirm my answer maybe is correct or not, just do it for me

thanks

Very good but I don't see any answers. If you will post your work I shall be happy to check it.

is 1mole

1)1mole

1. The reaction of potassium permanganate and iron salt in acidic medium can be represented by the following balanced equation:

2 KMnO4 + 3 FeSO4 + 2 H2SO4 -> K2SO4 + 2 MnSO4 + 3 Fe2(SO4)3 + 2 H2O

From the balanced equation, we can see that 2 moles of KMnO4 react with 3 moles of FeSO4. Therefore, the correct answer is: 2 moles of Mn with 1 mole of Fe.

2. Potassium permanganate acts in acidic medium in titrimetric analysis. It is commonly used as an oxidizing agent in the presence of acid to determine the concentration of reducing agents.

3. When starch is used in iodiometric titration, the color changes from colorless to blue-black at the end point. This color change occurs due to the formation of a complex between iodine and starch.

4. The oxidation state of chromium in potassium dichromate is +6. In this compound, each chromium atom is bonded to six oxygen atoms, resulting in a total oxidation state of +6 for chromium.

5. The correct answer is: Sodium oxalate. Sodium oxalate is not considered a primary standard in analytical chemistry, as it may contain impurities that can affect its accuracy in concentration determinations.

6. A standard solution is a solution of known concentration. It is prepared by accurately weighing or measuring a known amount of substance and dissolving it in a solvent to a known volume.

7. A substance that is not available in a pure form can be standardized by titrating against a substance of known concentration. In this process, the substance of known concentration reacts with the substance of unknown concentration until the reaction is complete, allowing determination of the unknown concentration.

8. A pure substance is a sample that does not change its chemical composition during storage. It is free from impurities and maintains its physical appearance over time.

9. When heating a substance prior to weighing, it is usually placed in a fume hood. This ensures that any volatile components are safely captured and do not escape into the laboratory.

10. Heating sodium bicarbonate before its use as a standard expels carbon dioxide only. The release of carbon dioxide gas is often observed during the heating process.

11. To find the concentration of the resulting solution, divide the amount of solute (3.47g of sodium carbonate) by the volume of the solution (250 milliliters).

12. The proper way to prepare a 0.025M solution from a 1.00M stock solution is to dilute 12.5 mL of the stock solution to 500 mL with a solvent.

13. The apparatus needed for the preparation of a solution of hydrochloric acid, HCl, from the concentrated solution include a measuring cylinder, burette, and volumetric flask. A crucible is not necessary for this process.

14. To find the new concentration of the HCl solution, divide the moles of HCl in the given volume (15 cm3) by the new total volume (500 mL).

15. Shaking the mixture well during the preparation of a solution is necessary to produce a homogeneous solution. This ensures that the solute is evenly distributed throughout the solvent.

16. Acids are added to water and not water to acid when diluting because the dissolution of acid in water is exothermic and can be potentially explosive. Adding acids to water allows for better control and prevents vigorous reactions.

17. During standardization of HCl with sodium carbonate titration, the pipette is rinsed with distilled water and thereafter with the Na2CO3 solution. This ensures that any remaining water or impurities from the previous step are removed before transferring the sodium carbonate solution.

18. To find the average volume of HCl used, add up the recorded volumes and divide by the number of measurements taken.

19. To find the concentration of HCl, divide the volume of HCl used by the volume of the sodium carbonate solution and multiply by the known concentration of the sodium carbonate solution.

20. In titration, the experimentally determined stoichiometric point of the titration is referred to as the equivalence point. This is the point at which the reactants are present in stoichiometrically equivalent amounts and can be determined by a suitable indicator or pH measurement.