Reference no: EM13833463
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