Untitled Deck Flashcards
(41 cards)
What is a standard solution?
A solution whose strength is known is called a standard solution.
Name the standard solution in KMnO4 Vs Mohrs salt solution titration.
Mohrs salt.
Name the standard solution in KMnO4 Vs oxalic acid titration.
Oxalic acid.
What is a primary standard?
A chemical substance whose standard solution can be prepared by dissolving it in water is called a primary standard.
Is NaOH a primary standard?
No.
Are molality and molarity same?
No.
What is titration?
The process of adding one solution from the burette to another in the conical flask in order to complete the chemical reaction involved is known as titration.
What is an indicator?
A chemical substance which changes colour at the end point.
What is end point?
The stage during titration at which the reaction is just complete is known as the end point of titration.
Why must burette and pipette be rinsed with the solution with which they are filled?
To remove any substance sticking to their sides, which otherwise would decrease the volume of the liquids to be taken in them.
What is a molar solution?
A molar solution is a solution which contains one gm mole of the solute in 1 litre of solution.
What is permanganometry?
Redox titrations involving KMnO4 as the oxidizing agent are called permanganometric titrations.
What is a redox reaction?
A reaction in which both oxidation and reduction takes place simultaneously is called a redox reaction.
Which is the oxidizing agent and reducing agent in the reaction between KMnO4 and Mohrs salt?
Oxidizing agent - KMnO4
Reducing agent - Mohrs salt.
Which is the oxidizing agent and reducing agent in the reaction between KMnO4 and oxalic acid?
Oxidizing agent - KMnO4
Reducing agent - Oxalic acid.
What happens to oxidizing agent and reducing agent in a redox reaction?
Oxidizing agent undergoes reduction and reducing agent undergoes oxidation.
What is the indicator used in KMnO4 titrations?
No indicator is used because KMnO4 acts as a self indicator.
Why does KMnO4 act itself as an indicator?
In the presence of dilute H2SO4, KMnO4 reacts with reducing agent (oxalic acid or Mohrs salt). When all the reducing agent has been oxidized, the excess of KMnO4 is not decomposed and imparts pink colour to the solution.
What is the end point in KMnO4 titrations?
From colourless to permanent light pink.
Why are a few drops of Con. H2SO4 added while preparing a standard solution of Mohrs salt?
Few drops of H2SO4 are added to prevent the hydrolysis of Mohrs salt.
Why should a burette with rubber pinch cock not be used in KMnO4 titrations?
Because KMnO4 attacks rubber.
Why should you heat the oxalic acid solution to about 60-70 °C before titrating with KMnO4 solution?
In cold, the reaction is very slow due to the slow formation of Mn2+ ions. Oxalic acid is heated to speed up the liberation of Mn2+ ions which then autocatalyze the reaction and thus the reaction proceeds rapidly.
Sometimes a brown ppt is observed in KMnO4 titrations. Why?
It is due to insufficient quantity of dilute H2SO4. Brown ppt is formed due to the incomplete oxidation of KMnO4.
What is the molecular formula of Mohrs salt?
FeSO4(NH4)2 SO4.6H2O.
